Poultry Diseases and Their Treatment

By Paul McMullin

M.Abubakar.Tahir

M.Sc.(Hons) Animal Nutrition

University of Agriculture Faisalabad
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M.Abubakar.Tahir

Amyloidosis
Introduction
A Coronavirus infection of chickens with a morbidity of 50-100% and a mortality 0-25%, depending on secondary infections. Infection is via the conjunctiva or upper respiratory tract with an incubation period of 18-36 hours. The infection spreads rapidly by contact, fomites or aerosol. Some birds/viral strains can be carriers for up to 1 year. The virus, which may survive 4 weeks in premises, is sensitive to solvents, heat (56°C for 15 mins), alkalis, disinfectants (Formal 1% for 3 mins). Poor ventilation and high density are predisposing factors.

Post-mortem lesions
   Oedema of pectoral muscles and subcutaneously on abdomen, lesions progress to necrosis and scarring of deep pectorals in convalescence. In layers the ovules may be intensely congested. Other lesions of 'classical' IB may be encountered.

Prevention
Live vaccines of appropriate sero-type and attenuation, possible reactions depending on virulence and particle size.

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Anatipestifer Disease, New Duck Syndrome, Duck Sepicaemia
Introduction
An acute or chronic septicaemic disease caused by Riemerella anatipestifer, syn Pasteurella, or Moraxella a. It affects ducks of any age, sometimes turkeys, and may also be isolated from chickens, game birds and wild waterfowl. Mortality is 2-75% in young ducks. Transmission is mainly direct, bird-to-bird, via toenail scratches, especially of the duckling foot, or through respiratory epithelium during respiratory disease. It can also be by faecal contamination of feed, water or the environment where survival of the infectious agent may be prolonged. Adverse environmental conditions and pre-existing disease are predisposing factors.

Treatment
Sulphonamides and potentiated sulphonamides are the products most commonly recommended for drinking water application. Subcutaneous injections of penicillin + dihydrostreptomycin, or streptomycin + dihydrostreptomycin are also highly effective.

Diagnosis
Isolation and identification. The disease has a complex aetiology and is predisposed by reduced ventilation.   
Salpingitis. methods as per Salmonella spp.
Post-mortem lesions
      Thickening of right-side myocardium. Formerly in-feed medication with nitrofurans was also used. Differentiate from
Treatment
Injection of streptomycin. good nest and hatchery hygiene. fumigation of hatching eggs. Dilation of the ventricle. Ascites is a disease of broiler chickens occurring worldwide but especially at high altitude. may be related to type of stock and strain). salmonellosis.
Ascites
Introduction
Associated with inadequate supplies of oxygen. or gentamycin at the hatchery is used in some countries. Severe muscle congestion. Dyspnoea. mortality 1-2% but can be 30% at high altitude. Morbidity is usually 1-5%. Perihepatitis. Recumbency. monitor sensitivity. and respiratory disease.
Signs
      Sudden deaths in rapidly developing birds. coli-septicaemia. Pericarditis. Lungs and intestines congested. Thickening of atrioventricular valve. General venous congestion. Possibly cyanosis. high altitude.
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.
Prevention
Eradicate from breeder population. inject eggs or poults with antibiotics. poor ventilation and physiology (oxygen demand. Poor development. Pulmonary arterial vasoconstriction appears to be the main mechanism of the condition. Progressive weakness and abdominal distension. Ophthalmitis. spectinomycin.

This may offer the ability to identify genetic predisposition.    
Liver enlargement. caused by Aspergillus fumigatus. Microscopic .
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. Thirst. especially in young chicks. Morbidity is usually low. in which the typical sign is gasping for breath. The fungus can infect plant material and many species of animals including birds and man. waterfowl. game birds. Vitamin C (500 ppm) has been reported to be of benefit in South America. etc. Spores are highly resistant to disinfectants. Sometimes the same organism causes eye lesions or chronic lesions in older birds. It affects chickens. Differentiate from broiler Sudden Death Syndrome and bacterial endocarditis. ducks. worldwide. there is usually little bird-to-bird transmission. but may be as high as 12%. Weakness. turkeys. Absidia etc.
Aspergillosis
Introduction
A fungal infectious disease. avoid any genetic tendency. penguins. Ascites.
Treatment
Improve ventilation. control respiratory disease.
Prevention
Good ventilation (including in incubation and chick transport). Mortality among young affected birds is 5-50%. Occasionally similar lesions are produced by other species ofAspergillus or even other fungi such as Penicillium.
Diagnosis
Gross pathology is characteristic. Rapid breathing. The infection has an incubation period of 2-5 days. Drowsiness. Pericardial effusion.cartilage nodules increased in lung.
Signs
 Acute        form: Inappetance. Transmission is by inhalation exposure to an environment with a high spore count. Silent gasping. Spleen small. Nervous signs (rare). A cardiac specific protein (Troponin T) may be measured in the blood.

Epidemic tremors for its effect in young birds.
Avian Encephalomyelitis Egg Drop
Introduction
Avian encephalomyelitis virus infection in laying bird causes inapparent infection or drops in egg production. quail. mortality none.M. trachea. Thiabendazole or Nystatin has been used in feed. See Avian Encephalomyelitis. pheasants and occurs in most poultry-producing countries. Morbidity 5-60%. turkeys.Tahir 2
 Chronic Forms:  Ocular discharge (ocular form only).
Prevention
Dry. Brain lesions may be seen in some birds with nervous signs.
Figure 8. 'Furry' airsacculitis in aspergillosis of an adult duck. Amphotericin B and Nystatin have been used in high-value birds. The powdery surface is dark green in colour. It affects chickens.
Post-mortem lesions
   Yellow to grey nodules or plaques in lungs. Differentiate from excessive exposure to formalin or vaccinal reactions in day olds and from heat stress in older birds. may have greenish surface. preferably after digestion in 10% potassium hydroxide.  Wasting.
Diagnosis
This is usually based on the signs and lesions and microscopic examination for the fungus. It may be confirmed by isolation of the fungus. Growth occurs in 24-48 hours and colonies are powdery green/blue in appearance. The means of transmission is unknown but
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. hygiene.Abubakar. plaques in peritoneal cavity. air sacs. typically by putting small pieces of affected tissue on Sabouraud agar. Conjunctivitis/keratitis.
Treatment
Usually none. Environmental spraying with effective antifungal antiseptic may help reduce challenge. good quality litter and feed.

Avian Encephalomyelitis. turkeys. The route of infection is transovarian with an incubation period of 1-7 days.
Diagnosis
History. Dull expression. incubation >10 days. Ataxia and sitting on hocks. Differentiate from Infectious Bronchitis. Epidemic Tremors
Introduction
Avian encephalomyelitis is a viral disease of the central nervous system of chickens. rising titre to AE virus. EDS76. Virus in faeces may survive 4 weeks or more. feed. It has a worldwide distribution. and there is serious disease in the progeny (see next section).
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. with an oral infection route. lateral transmission is probably by the oral route.The embryo protection test has been used in the past.
Treatment
None. attenuated or not. some lateral.
Prevention
Vaccination of breeders/layers at 9-15 weeks. subsequent disease in progeny if breeders. Morbidity 5-60% depending on the immune status of the majority of parents. Predisposed by immunosuppression. now Elisa is used more commonly. small (5-10%) and lasting no more than 2 weeks.
Post-mortem lesions
 None. lentogenic Newcastle disease. Paralysis.
Signs
  Drop in egg production. transmission occurs over about 1-2 weeks. Serology .
Signs
     Nervous signs. Vertical transmission is very important. Imbalance. In breeders there may be a drop in hatchability of about 5%. Immunity is usually long lasting. water etc. Virus in faeces may survive 4 weeks or more. and quail. pheasants.probably by faecal contamination of environment. mortality high.

Diagnosis
A presumptive diagnosis is based on the history. Microscopic . and/or viral isolation may be carried out if required.
Avian Influenza-Highly Plague
Introduction
Pathogenic
(HPAI). The cause is a virus.
Post-mortem lesions
    Gross lesions are mild or absent. pigeons. neck and wings. There may be focal white areas in gizzard muscle (inconstant). ducks. The virus infects chickens. pheasants. the equivalent of the World Health Organisation for animal diseases. A few recovered birds may develop cataracts weeks after infection. Tremor may be inapparent but is accentuated if chicks are held inverted in the hand. and isolates are designated sero-type/ species/location/reference number/year/subtype designation(H/N). Highly pathogenic forms are usually of the H groups 5 and 7 and may now be identified (if H5 or H7) by the presence of a sequence at the haemagglutinin cleavage site that codes for multiple basic amino acids. Histopathology is usually diagnostic and IFA.
Prevention
Vaccination of breeders at 9-15 weeks. Mycotic Encephalitis. especially in turkeys. Brain abscess. Marek's disease. Differentiate from Newcastle disease. quail.2 .
Tremor of head.
Treatment
None. and lack of significant lesions. partridges. This is a test in which the virus is inoculated into susceptible chickens that are then kept under observation. toxicities. its pathogenicity is variable. riboflavin). Effectively all
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. Immunity is long lasting.
Fowl
One of only two 'Class A' diseases of poultry targeted for emergency disease control measures by OIE. Enterococcus hirae infection. The definitive classification of high pathogenicity is an intravenous pathogenicity test (IVPI) in 6-week-old chickens result of greater than 1. A. EE (especially in pheasant in the Americas). and ostriches. signs. The embryo protection test has been used in the past. now Elisa is used more commonly. The higher the proportion of the chickens dying or showing signs the higher the IVPI. attenuated or not. Orthomyxovirus type A. vitamin deficiency (E. In addition official control measures disrupt trade in poultry products from affected areas. This viral disease can cause exceptionally high mortality. turkeys.nonpurulent diffuse encephalomyelitis with perivascular cuffing.

Apathogenic and mildly pathogenic influenza A viruses occur worldwide. in northern Italy. clothing.
Post-mortem lesions
  Inflammation of sinuses. Avian Influenza is a potential zoonosis. Diarrhoea (often green). USA. Depression. Coughing. equipment. in the years 1983-84. It can remain viable for long periods in tissues. trachea. reduced feed consumption. Morbidity is high but mortality usually relatively low. Pakistan. even with 'low pathogenicity' strains. can survive 4 days in water at 22°C. especially faeces. A serious outbreak occurred in The Netherlands in 2003 with a few linked cases in Belgium and one in Germany. Cessation of normal flock vocalisation. air sacs and conjunctiva. It is inactivated by a temperature of 56°C in 3 hours and 60°Cin 30 min. Avirulent in one species may be virulent in others. but possibly by the conjunctival or respiratory route and the incubation period is 3-5 days. Marked loss of appetite. Ovarian regression or haemorrhage. waterfowl. from December 1999. 550%. The small number of human deaths associated with HPAI appear to have resulted from direct exposure to infected birds on farm or in markets. The route of infection is probably oral initially. Because of this. The virus replicates mainly in respiratory tissues of chickens and turkeys but in the intestinal tract of clinically normal waterfowl. Mexico and. Nasal and ocular discharge. More recently outbreaks have occurred in Australia.
Signs
           Sudden death. Pasteurella) may increase mortality. by acid pH. drinking water. and the high mortality that 'low-path' AI can cause in turkeys. Outbreaks due to HPAI were recorded in the Pennsylvania area.birds are considered to be at risk of infection. Swollen face. Drops in egg production.
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. Italy). OIE and other bodies are currently examining ways to improve control of LPAI. Infections with other pathogens (e. Highly pathogenic avian influenza A (HPAI) viruses of the H5 and H7 HA subtypes have been isolated occasionally from free-living birds. Cyanosis of comb/wattles. Nervous signs such as paralysis. The virus is moderately resistant. Transmission is by direct contact with secretions from infected birds. conjunctivitis or severe pneumonia. Broken contaminated eggs may infect chicks in the incubator simulating vertical transmission.g. See current OIE records for up to date information on distribution of HPAI. It can result in inapparent infection. by oxidising agent and by formalin and iodine compounds. H5 viruses of low pathogenicity may become highly pathogenic usually after circulating in poultry flocks for a time (Pennsylvania. over 30 days at 0°C.

other respiratory infections. lesionless carriers of highly pathogenic virus. etc. Confirmation is by viral isolation in chick embryo. Commercial Elisa test kits are now available. fowl cholera. 21-day interval to re-stocking should be followed. HA+. North and South America. Congenitally infected birds tend to remain
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. Transmission is by congenital infection from antibody-negative females.
Avian Leukosis (Serotype J). Morbidity is low. with considerable strain-to-strain variation.
Prevention
Hygiene. This condition has until now been seen only in meat-type chickens. bacterial sinusitis in ducks. isolation. though there is high mortality of affected birds. Differentiate from Newcastle disease. The incubation period is 10-20 weeks. lateral transmission by faecal-oral route (this declines as the bird ages). disinfection. DID+. To be effective inactivated vaccines must be the right subtype for the particular situation (H5 will not protect against H7 and vice versa). while ducks may be symptomless. cleaning. as with many such tests occasional false positive reactions can occur.
Diagnosis
A presumptive diagnosis may be made on history and postmortem lesions. vaccinated birds may remain carriers if exposed to the infection. correct disposal of carcases. Myelocytomatosis
Introduction
Caused by an avian retrovirus.
Treatment
None. Turkey lesions tend to be less marked than those of chickens. Survivors can be expected to have a high degree of immunity but may harbour virulent virus. However. It has occured in Europe. controlled marketing of recovered birds. but good husbandry. NDV-. nutrition and antibiotics may reduce losses. Subcutaneous oedema of head and neck. Haemorrhage in proventricular and gizzard mucosae and lymphoid tissue of intestinal tract. In outbreaks a regime of slaughter. Muscles congested. Vaccines have been used in recent outbreaks in Mexico and Pakistan. Eradication by slaughter is usual in chickens and turkeys.     
Necrosis of skin of comb and wattles. infectious laryngotracheitis. Minimise contact with wild birds. The agar gel precipitation test is non-group-specific and is used to confirm any positives. quarantine. although it may reduce losses initially. Vaccination is not normally recommended because. all-in/all-out production. Dehydration. bleeding and vaccination needles.

Treatment
None.antibody negative.most but not all. often with tumour foci. ultimately identification of virus by isolation and/or PCR. particularly of the sternum. Splenomegaly and enlarged kidneys also occur. Many are asymptomatic. shed virus and develop tumours. 'nonshedders' .tumours usually contain well-differentiated myelocytes. liver. birds with egg antigen will be antibody negative. Two cell types may be found in the same tumour. PCR testing of embryonally infected chicks using DNA testing is uniformly positive for blood and faecal samples. histology. Handle clean lines before infected lines. ribs.
Post-mortem lesions
    Liver enlargement. Persistent low mortality.80% produce infected chicks. Critical hatchery practices:     Separate infected and uninfected lines. Lymphoid Leukosis. Microscopic . Virus survival is poor but sufficient to allow cross contamination in hatcheries and on farm in rear.
Prevention
Checking of antigen in the albumen is a basis for eradication .
Signs
      Depression. Serology . Enlargement of abdomen. sacral joint. age. Prevent/ reduce cross-infection in hatchery and on farm.only 3% produced infected chicks. Minimise stress. Differentiate from Marek's disease. preferably on separate hatch days and in separate machines. Emaciation.
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. Most characteristically are chalky white tumours in the bone marrow. There is also evidence that it is slightly more sensitive than conventional testing.an Elisa test is aviailable to identify antibody positive birds. Separation in vaccination. lesions. 'Shedders' . Loss of weight.
Diagnosis
History.

Leukosis/Sarkoma Group
Introduction
Lymphoid
Leukosis. osteopetrosis.egg layers are generally more susceptible to lymphoid leukosis. initially in the bursa. erythroblastosis. In lymphoid leukosis the incubation period is about 4-6 months. Egg production is somewhat reduced. The causative viruses are rapidly inactivated at ambient temperature and on exposure to most disinfectants. Morbidity is low but mortality high. Enlargement of abdomen.
A complex of viral diseases with various manifestations such as lymphoid leukosis. It affects chickens worldwide with susceptibility varying considerably among different strains and types of stock . Liver may be very large. Vertical transmission is most important by infection of the egg white in infected breeders (who are long-term carriers). it may be as short as 6 weeks for some of the other manifestations.Farm practices:     Brood and rear lines separately and maintain separate for as long as possible. lesions. then liver. other tumours. Persistent low mortality. There may be increased susceptibility to other infectious diseases due to damage to the immune system. Many are asymptomatic. especially in young birds.
Signs
      Depression. Mortality tends to be chronically higher than normal for a prolonged period. lateral transmission is poor but infection may occur by the faecal-oral route. spleen. age. coligranuloma. Loss of weight. Differentiate from Marek's disease. Avoid migration errors (birds unintentionally moving between pens). kidney etc. myeloblastosis (see Sero-type J).cells lymphoplastic
Diagnosis
History. Emaciation. myxosarcomas. cytology. Delay live vaccine challenges.
Post-mortem lesions
  Focal grey to white tumours. Minimise group sizes. Microscopic . liver or bursa.
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. fibrosarcomas.
Avian Leukosis.

Loss of voice. Conjunctivitis. vertical transmission is uncertain. eradication . Africa. There is rapid lateral transmission with infection by aerosol through the respiratory route. Ocular and nasal discharge.
Avian Rhinotracheitis 'Swollen Head Syndrome'
Introduction
A viral disease of chickens. Two subgroups have been identified on the basis of the G-protein sequence: A (original UK isolates) and B (original southern Europe isolates).
Signs
       Decreased appetite. Diffuse lymphoid tumours in an enlarged liver from a mature broiler parent hen. weight gain and feed efficiency. first isolated from poults in South Africa in 1978. morbidity is 10-100% and mortality can be 110%. The incubation period is 5-7 days. It is caused by a pneumovirus of the Paramyxoviridae family. turkeys (see separate summary). This was a case of Myelocytoma Avian Leukosis (Sero-type J). Dyspnoea. Snick. Facial and head swelling (though this can occur in other conditions).Treatment
None. guinea fowl and possibly pheasants seen in Europe.
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. all-in/all-out production. fomites can be important in moving infection between farms. As for many infections.checking of antigen in the albumen is a basis for eradication (see Sero-type J for details). South America and North America.
Figure 9. control arthropods.
Prevention
Good hygiene.



Sinusitis.

Post-mortem lesions
  Serous rhinitis and tracheitis, sometimes pus in bronchi. If secondary invasion byE. coli then pneumonia, airsacculitis and perihepatitis. Congestion, oedema and pus in the air space of the skull occurs in a proportion of affected birds due to secondary bacterial infections.

Treatment
Antibiotic not very effective. Control respiratory stressors, chlorination of drinking water, multivitamins.

Prevention
All-in/all-out production, vaccination (degree of cross protection between A and B types remains to be established). Live vaccines can reduce clinical signs and adverse effects, inactivated vaccines may be used in breeders prior to lay.

Figure 10. Pus in skull bones. This is a common sequel to avian pneumovirus infection in both chickens and turkeys.

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Beak Necrosis
Introduction
A condition seen in chickens and turkeys caused by excessively fine mashed feeds.

Signs
   Feed accumulates along edges of lower beak leading to distortion and necrosis of horny tissue. Has been associated with curled tongue in turkeys in the past. This may also be associated with ulcers in the roof of the mouth (palate) which can be confused with some forms of mycotoxicosis.

Post-mortem lesions
 See signs.

Diagnosis
Clinical signs, exclusion of other causes of similar signs.

Treatment
Not usually sufficiently severe to justify medication. Mild water sanitation may help control secondary infections in the affected tissues.

Bedbug Infestation
Introduction
A condition of poultry, pigeons (and mammals) caused by infestation with the external parasite Cimex lectularius. The parasites are up to 5 mm long and feed at night. It occurs mainly in subtropical and some temperate areas. Adult parasites can survive for 1?12 months in the environment without feeding. Eggs laid by the adult parasites hatch in 4?20 days, there are five nymphal stages each of which feed on birds. Growth to adult parasite takes 1?3 months, depending on temperature.

Diagnosis
Identification of the parasite. Differentiate from other blood sucking parasites.

Treatment
Appropriate insecticide treatment of the environment, in particular the cracks and crevices where the parasites hide during the daytime.

Prevention
Thorough treatment of the empty building at turn-around with an appropriate insecticide. Fumigation is also helpful.

Big Liver and Spleen Disease
Introduction
This condition was first seen in Australia in 1980. It is now known to be caused by an Avian Hepevirus. Related viruses have been reported to cause a hepatitis/splenomegaly syndrome in the USA, sub-clinical infection in pigs and Type E Hepatitis in man. The pig origin virus can cause disease in man, but avian hepeviruses are believed not to be zoonotic. The lesions are associated with deposition of antigen/antibody complexes in tissues. Only chickens are known to be naturally affected, most commonly broiler parents in lay. Natural infections have only been demonstrated in chickens over 24 weeks of age though it is possible that vertical transmission and/or infection in rear occurs with a subsequent period of latency. Transmission is usually by the faecal/oral route. Faecal contamination of drinking water is likely to be an efficient means of spread of this infection. Embryos inoculated intravenously become persistently antigen positive.

Signs
    Chronic under production or egg drops of up to 20%. Mortality of up to 1% per week for 3-4 weeks. Anaemia. Premature moulting.

Thickened skin under foot pad. in embryos. Reduced feed intake and blood sugar can precipitate fatty liver and kidney syndrome. Pale livers and kidneys in fatty liver and kidney syndrome.
Treatment
No specific treatment known. It may be helpful to control other conditions which may be occurring at the same time. Scabs around eyes and beak.
Prevention
Thorough cleaning and disinfection after depletion of an affected flock.
Post-mortem lesions
  See signs. Must be confirmed by laboratory tests. Drinking water which is well chlorinated should be helpful in reducing challenge by this route. webbing between toes.
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. Serological tests (agar gel immunodiffusion) may be used to detect either the specific antigen (which is likely to be positive first) or the antibody response to it.   
Lung congestion Ovarian regression Yolk peritonitis Pale foci and haemorrhages in pancreas.
Signs
      Poor growth. Leg weakness. Sudden deaths in fatty liver and kidney syndrome. Viral particles may be demonstrated in bile. Including Fatty Liver and Kidney Syndrome
Introduction
Biotin deficiency has occured in turkeys and chickens in many countries but is now rare in birds consuming properly formulated feeds.
Biotin Deficiency. Good biosecurity. Histopathology may also be used but the findings are not specific to this condition. Allin/all-out production. Elisa tests have been developed experimentally. A RT-PCR test may be used to detect viral RNA in tissues. Chondrodystrophy.
Diagnosis
Typical signs and lesions.

response to treatment/prevention. bedbugs.
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. Drop in egg production.Diagnosis
Signs. lesions. Scabs around vent. Check flocks regulary for rapidly moving insects at the base of the feathers on the abdomen or around the vent. Irritation.naturally present in many raw materials. Lice eggs stuck to feathers. may be some feather damage and crustiness of skin. Loss of vent feathers. has very low bioavailability. Loss of condition. Differentiate from mites.
Signs
        Lack of thrift in young birds. Differentiate from pantothenic acid deficiency (skin lesions).
Treatment
Addition of biotin in feed or water.
Post-mortem lesions
 Usually none. The parasites are 1-6 mm in size and their life cycle takes about 3 weeks.
Treatment
Malathion powders and pyrethroid sprays where approved for bird application. Parasites on birds.
Biting Lice
Introduction
Various species of lice are common external parasites of poultry worldwide.
Prevention
Supplementation of diets with biotin .
Diagnosis
Identification of the parasites. Away from birds adults survive about 4-5 days. especially around vent. Menocanthus stramineus is the most pathogenic and is said to be capable of causing anaemia in heavy infestations. They are spread by direct contact between birds and by litter etc. Crusty clumps of eggs ('nits') may be visible at the base of feathers.

Examine for lice regularly.
Blackfly Infestation
Introduction
Grey-black hump-backed flies.
Diagnosis
Anaemia. 5 mm long and found in North and South America that are external parasites of birds and mammals.
Post-mortem lesions
 Anaemia. although these insects can travel up to 15 miles. The condition tends to occur near to rapidly flowing streams.
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. Swarms of flies. Effective removal of all organic material at flock depletion should be practised in all-in/all-out production systems. especially in autumn and winter and treat if required. Eggs and larvae survive through the winter to cause new infestations in the following year.
Signs
  Anaemia in young birds. The flies transmit leucocytozoonosis and also a filarial parasite in ducks. Biological control using a strain of Bacillus thuringensis has had some success and is preferable to insecticides. season. as the larvae within eggs are not killed by most products. It is usually necessary to treat twice at a 7-10 day interval to fully control the condition. Weekly treatments are required.Prevention
Avoid direct contact with wild and backyard poultry. local history.
Prevention
Similar measures as for mosquito control.
Treatment
Treatment is difficult.

Post-mortem lesions
    Possibly no significant lesions.
Treatment
Remove source of toxin. because it rests on the litter. Feathers may be easily pulled (chicken only). ducks and other waterfowl occurring worldwide and caused by a bacterial toxin produced byClostridium botulinum mainly types A / C. is also quite typical. This will reduce the risk of botulism both in the poultry and in any grazing animals on land where poultry litter is spread. mouse toxicology on serum or extract of intestinal contents. turkeys. suspect food and stagnant ponds. especially in hot weather. A soiled beak. weakness.Botulism
Introduction
A condition of chickens. wings then neck. Mild enteritis if has been affected for some time. The toxin is produced in decaying animal (usually carcases) and plant waste. supportive treatment if justifiable.
Prevention
Preventing access to toxin. It has also been suggested that poultry carcases lost in litter can be a cause of botulism in cattle grazing land or consuming silage where poultry litter has been spread. and toxin-containing material (pond-mud.
Diagnosis
History. carcases. maggots) is consumed by the birds. Toxin may also be produced by the bacteria in the caecum. signs. antibiotics. then sudden death. progressive flaccid paralysis of legs. Differentiate from acute Marek's disease ('Floppy Broiler Syndrome') by histology of the brain.
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.
Signs
   Nervous signs. The single most important measure is careful pick-up and removal of all dead birds on a daily basis. The toxin and bacterial spores are relatively stable and may survive for some time in the environment. Affected broilers tend to settle with eyes closed when not disturbed. Maggots or putrid ingesta may be found in the crop. Morbidity is usually low but mortality is high. selenium.

nematode parasites of poultry and game birds.
Signs
 None.
Prevention
Good litter management and handling. They are found worldwide. the cause of Blackhead. give way to scar tissue. control of leg problems.
Caecal Worm
Introduction
Heterakis gallinae. bacteria.5 cm in length that occur in the caecum. Morbidity may reach more than 50% but the condition is not fatal. and a four-week prepatent period. There is an incubation period of 2 weeks for eggs to embryonate.
Signs
 Swelling over the keel bone with bruising and discolouration.
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. Earthworms may be transport hosts for eggs.
Post-mortem lesions
 Inflammation of sternal bursa along the keel bone which may. and infection withStaphylococcus spp.Breast Blister
Introduction
A complex condition of chickens and turkeys occurring worldwide associated with trauma.
Diagnosis
Based on lesions. leg weakness. The meaning of the technical terms relating to parasite life cycle are defined in the glossary. Morbidity is high but it is not associated with mortality. up to 1. in chronic cases. are small whitish worms with a pointed tail. Poor feather cover and caked or wet litter are predisposing factors. Heterakis gallinaeeggs and larvae are a transport hosts for Histomonas. or paratenic hosts with partially developed (L2) larvae.
Treatment
Not usually appropriate. Infection is by the oral route.

Prevention
Avoiding access to earth and earthworms.
Calcium Tetany
Introduction
A metabolic disease of chickens. especially broiler parents. and the embryonated egg.
Figure 11. Predisposing factors include heat stress with reduced feed intake and panting. Levamisole. Routine anthelmintic treatment.
Treatment
Flubendazole.
Diagnosis
Adults can be seen in caecal contents at post-mortem examination. The egg may be ingested directly by a chicken.Post-mortem lesions
 Inflammation of caecum. possibly with nodule formation.
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. or by an earthworm which is in turn ingested by a chicken. Death from respiratory and cardiac failure. an undeveloped egg as found in fresh faeces. are effective.
Signs
  Paralysis. The life cycle ofHeterakis showing the location of adults.

There is an annual cycle with increased risk of infection in the summer months in some countries. and response to treatment. managing birds for maximum uniformity. biofilm or engulfed by protozoa. Campylobacter jejuni infection is not currently considered to be pathogenic in poultry though a Campylobacter-like organism is considered to be the cause of 'Vibrionic Hepatitis'. In poultry they tend to multiply in large numbers in the hindgut. lesions. Differentiate from IB 793b. Campylobacters are a significant cause of enteritis in man.
Prevention
Keep pullet flocks on low calcium diet until 5% production hen/day. All campylobacters are delicate organisms that survive for relatively short periods outside the host unless protected by organic material.
Diagnosis
This is made on signs. There are indications that plantar pododermatitis. principally in the caecae.
Treatment
Provide 5 gm of oyster shell per hen on 3 successive days along with vitamin D in drinking water. Active ovary with egg in oviduct. carcase quality and litter quality are better on farms which tend to have Campylobacter-negative stock. It may be that management that favours dry litter reduces the risk of infection and/or transmission within the flock.
Campylobacter Infection
Introduction
Campylobacter spp. Infected poultry are a potential reservoir of this zoonosis. Congested lungs. other acute infections and other causes of sudden death. are bacteria that commonly infect a broad range of livestock species. lack of other significant lesions.
24
. Campylobacter jejuni is the commonest species found in poultry. The reason for this is unclear. pets and wild animals.Post-mortem lesions
   Cyanosis.

The organism is sensitive to air so swabs should be collected into transport medium and other samples placed in airtight containers with minimal airspace. avoidance of contact with pets and other farmed species. sourcing of water from high quality supplies. For this reason it may be difficult to stop the spread of infection between houses once it becomes established in one house. Research is ongoing on the development of vaccines. cloacal swabs or composite faeces. Key aspects of this include effective sanitation of drinking water. In practice the success of this will also depend upon the degree of environmental contamination by the organism.
Prevention
In principle. good hand hygiene by stockmen. as well as processing plant technologies to reduce carcase contamination.
Post-mortem lesions
 None.
Treatment
Not required on clinical grounds. Samples should be tested as quickly as possible after collection.
25
. housed poultry can be maintained free of Campylobacter infection by consistent application of excellent biosecurity. Insects and rodents may act as a means of transfer of the infection from the general environment into the poultry buildings. and changing of overalls and boots on entering bird areas. phage treatments and competitive exclusion approaches.Signs
 None. Many infections are introduced during thinning or other forms of partial depopulation.
Diagnosis
Isolation of the organism from caecal contents.

crop.
Diagnosis
Lesions. Candida albicans and the condition is seen worldwide. occasionally proventriculus and intestine. oesophagus. Slow growth. copper sulphate (1 kg/tonne feed) for 5 days. Morbidity and mortality are usually low. Ensure good hygiene. characterised by thickening and white plaques on the mucosa.
Treatment
Nystatin (100 ppm in feed) for 7-10 days.
Prevention
Avoid excessive use of antibiotics and other stressors.Candidiasis. possibly confused or masked by signs of the primary disease. Thrush
Introduction
A disease of the alimentary tract of chickens. and sometimes other birds and mammals. The fungus is resistant to many disinfectants. A finely divided powder of copper sulphate (where approved) at 200gm/tonne continually or to 14-16 weeks in replacement pullets. Raised focal lesions may slough into lumen as caseous material. Moniliasis. Poor appetite. proprionic acid.
26
.g. Diarrhoea. microscopic examination of a digested smear (heat in 10% potassium hydroxide) to demonstrate the hyphal forms of the yeast in the tissues. sodium or calcium proprionate at 1 kg per tonne continually.
Signs
    Dejection. Control of Candida through drinking water is sometimes practised with chlorination (e. especially in the crop but sometimes in the proventriculus. or copper sulphate 1gm/2 litre water for 3 days if approved locally. intestine and cloaca.
Post-mortem lesions
  White plaques in mouth. histopathology. The cause is a fungal yeast. smooth and with a yeasty smell. turkeys. and associated with gizzard erosion. Colonies of this fungus appear as white to ivory colour. The route of infection is normally oral and the organism is often present in healthy animals with disease occurring secondary to stress and poor hygiene.

Take care to provide fresh clean feed and water. anaemia. Soluble multivitamins and/ or methionine may be of some benefit in some circumstances. and strain of bird.
Prevention
Proper density and temperature.Chlorox. Provision of a diet that closely matches the nutritional requirements of the stock concerned. control ectoparasites. complying with local regulations and any relevant codes of practice. This is economical and effective.g.
Post-mortem lesions
  Skin wounding related to particular signs exhibited. Predisposing factors include overcrowding. boredom. feed form (mash takes longer to consume than pellets).
Treatment
Correct any husbandry problems. tenosynovitis and other diseases affecting mobility. Feather pecking
Introduction
A complex multifactorial behavioural problem of poultry and game birds seen worldwide. wings. head. sodium hypochlorite) at 5 ppm. distribution of lesions. post-mortem cannibalism. Beak trimming may be necessary. face. nutritional deficiencies.
27
.
Signs
  Pecking at feet (especially young chicks) and vents (adult layers and turkey poults 812 days old). high temperatures. Feather-pulling. uncontaminated by fungi. low light level. It should be repeated periodically. Morbidity is usually low but mortality is high among affected birds.
Diagnosis
Age. through shafts of light in the house).
Cannibalism. excessive light intensity or variation (e. Generalised anaemia. If so it should be carried out carefully by trained operators. Differentiate from bacterial dermatitis.

small intestine or caecum.
28
. obsignata in the small intestine. C. Wasting Poor growth. effective cleaning of houses. Fenbendazole has been shown to have high efficacy .
Signs
    Diarrhoea. Morbidity and mortality are usually low. contorta in the crop and oesophagus. Worm eggs take about 20 days to embryonate with an L1 larvae. prepatent period about 21-25 days according to species. Infection is by the oral route. The worms are 7-18 mm long. Differentiate from other causes of enteritis.05 mm wide and hair-like in appearance. C. game birds and pigeons ofCapillaria species.Hairworm Infection
Introduction
Nematode parasitic worms of poultry.
Diagnosis
This may be by a combination of macroscopic examination. Levamisole. Hairworms in mucosa of crop.
Prevention
Separation of birds from possible transport and intermediate hosts. some are transmitted direct from bird to bird. seiving intestinal contents. Some species have earthworms as intermediate hosts.
Post-mortem lesions
  Enteritis. or characteristic worm eggs in faeces in patent infections. Dejection. about 0. Worm eggs in the environment are resistant.
Treatment
Coumphos has been licensed in some markets.other approved benzimidazoles can be expected also to have activity.Capillariasis .

In the USA it is called 'Inflammatory Process'. coli. but the affected birds are not readily detectable prior to slaughter.
Prevention
Toe scrapes at 15-25 days of age when feather cover is poor are the most likely predisposing factors.
Signs
 Affected flocks tend to have poorer than average productivity and uniformity.
Diagnosis
Typical lesions. Routine monitoring of skin damage at about 25 days of age may be helpful in fostering good practices. though most of the birds showing toe scrapes will not go on to develop cellulitis. The condition is caused by infection of. often minor. Many affected birds have no other lesions and are reasonably well grown. which can replicate in the tissues. It typically occurs between skin and muscles and between muscles and may be an incidental finding in a range of conditions. particularly broiler chickens. skin wounds by particular strains of E.
29
.
Post-mortem lesions
 Typically it presents as exudate ranging from liquid and pale cream pus to yellowish solid plaques of caseous material under the skin of the abdomen and/or in the leg.Cellulitis
Introduction
Cellulitis is literally an inflammation of connective tissues. Careful flock management with a view to reducing toe wounds has the greatest impact in controlling cellulitis. If identified at a thinning there may be time for antibacterial treatment to have some benefit for those birds in the early stages of the problem.
Treatment
Treatment would not be possible if the problem is identified at a final depletion. However its main importance is as a cause of condemnation in meat poultry. Many meat inspectors become skilled at detecting subtle differences in skin colour in the affected birds.

Gangrenous dermatitis on feet. Sudden rise in mortality (usually at 13-16 days of age). Acute mycotic pneumonia. chloroform. Hypochlorite appears most effective in vitro. may be beneficial. If gangrenous dermatitis is a problem then periodic medication may be required. heat (70°C for 1 hour. The virus is resistant to pH 2.g. 80°C for 5 minutes) and many disinfectants even for 2 hours at 37°C.Chicken Anaemia
Introduction
A viral disease of chickens caused by Chicken Anaemia Virus or CAV.
30
. poor litter quality). Gumboro. PCV of 5-15% (normal 27-36%).
Treatment
Good hygiene and management. Mortality is typically 5-10% but may be up to 60% if there are predisposing factors present such as intercurrent disease (Aspergillosis.
Signs
    Poor growth. Discoloured liver and kidney. Inclusion body heptatitis etc. and control of other diseases as appropriate. Prior to confirmation that it is in fact a virus it was known as Chicken Anaemia Agent or CAA. Atrophy of thymus and bursa. demonstration of ongoing sero-conversion in parent flock. legs wings or neck.
Post-mortem lesions
      Pale bone marrow. Transmission is usually vertical during sero-conversion of a flock in lay. ether. virus may be isolated in lymphoblastoid cell line (MDCC-MSB1). lateral transmission may result in poor productivity in broilers. Pale birds.
Diagnosis
Gross lesions.) or poor management (e. No clinical signs or effect on egg production or fertility in parent flock during seroconversion.

mortality 5-40%. Inappetance. Their use may be restricted to those flocks that have not sero-converted by. Intercurrent salmonellosis and.
Chlamydiosis. Fibrinous pericarditis. Conjunctivitis. or IFA.Prevention
Live vaccines are available for parents. Wasting. Weakness. ducks. Depression. It is transmitted by contact. rarely chickens. phenolics are less so. say. especially pigeons and robins. perhaps. Weight loss. but occurring probably worldwide. Morbidity is 50-80%. Psittacosis. faecal dust and wild bird carriers. a bacterium of highly variable pathogenicity. Ornithosis
Introduction
An infection of turkeys. Production drops in naive laying flocks
Post-mortem lesions
    Vascular congestion. other infections may be predisposing factors.
Signs
          Respiratory signs. psittacines. Serology: antibodies develop 3-6 weeks after infection. Occasional transient ataxia in pigeons. Nasal discharge. They should be used at least 6 weeks prior to collecting eggs for incubation. Iodophores and formaldehyde are effective disinfecting agents.
31
. 15 weeks. It is a 'Scheduled Disease' rarely diagnosed in UK. their degree of attenuation is variable. Elementary bodies are highly resistant and can survive in dried faeces for many months. Greenish-yellow diarrhoea. and may be detected by SN. Airsacculitis. caused by Chlamydia psittaci. man. Immunity: there is a good response to field challenge (in birds over 4 weeks of age) and to attenuated live vaccines. pigeons. Elisa. Egg transmission does not occur.

Duck septicaemia.
Chondrodystrophy. In turkeys it may be an inherited deficiency of galactosamine. This condition is seen in chickens. Lameness. signs. Serology: complement fixation. may rupture in pigeons. lesions. biotin. choline.
Prevention
Biosecurity. Fibrinous pneumonia. shortened bones. folic acid.    
Perihepatitis. Slipped Tendon or Perosis
Introduction
Caused by deficiency of manganese. niacin may also be involved). either singly or in combination (although deficiencies of pyridoxine.
Diagnosis
History. exclusion of wild birds.
32
. Necrotic foci in liver. Elisa and gel diffusion. zinc. In embryos parrot beak. ducks and turkeys. Distortion of hock. Spleen enlarged and congested.
Treatment
Tetracycline (200-800 ppm in feed for 3-4 weeks) and/or quinolone medication and supervised slaughter.
Live and inactivated vaccines are protective although the former result in carriers and the latter require several applications.
Differentiate from Duck viral hepatitis. Intracytoplasmic inclusions are helpful but confirmation requires demonstration of causal organisms (Giemsa stain. IFA). Slipping of Achilles tendon (or perosis). Congested lungs and air sacs in the turkey.
Signs
      Short legs. Malposition of leg distal to hock.

Lateral slipping of tendon. This disease is not very common in commercially reared turkeys though most turkey growers receive preventative medication for at least part of their lives.
Signs
     Huddling. rickets. The contents may be haemorrhagic or be watery with white material shed from the mucosa. ruptured ligaments. Five species of Eimeria have been identified that cause lesions in turkeys. Depression. adenoides affects the caecae and rectum.
Diagnosis
Lesions. of which two are associated with significant disease effects. gallopavonis and E. Differentiate from twisted leg.
Coccidiosis of Turkeys
Introduction
Infection of turkeys with Eimeria spp. E. correct mineral balance. while E.Post-mortem lesions
    Shortening and thickening of long bones.
Post-mortem lesions
 The affected area of intestine shows thickening of the wall and dilation. Weight loss. Watery diarrhoea that may occasionally be blood stained or contain clumps of mucus or shed mucosa. Tucked appearance. while E. analysis of feed.
33
. ruffled feathers. vitamins. no value to affected bird. Tibia and metatarsus bowed. meleagridis affect the lower small intestine rectum and caecae. Shallow trochlea. dispersa is found in the small intestine.
Prevention
Addition of manganese. E.
Treatment
For flock proceed as for prevention. infectious synovitis. meleagrimitis affects the upper small intestine. infectious arthritis. choline.

show some spotty congestion and have abnormal contents due to the sloughed epithelium. Differentiate from necrotic enteritis. Diclazuril is also used for this purpose.
34
. Dosage levels of ionophores may be critical to efficacy and safety. The intestines are dilated. meleagrimitis. Sulphonamides (e. The exudate can range from semi-liquid to solid white cores.
Figure 38.
Prevention
The ionophore coccidiostats lasalocid and monensin are routinely used in turkey growers. Turkey caecal coccidiosis caused by E. Amprolium. lesions. microscopic exam of scrapings (oocysts.g.
Figure 37. Salinomycin is toxic for turkeys even at very low doses. Sulphaquinoxaline). gamonts). adenoides. Exposure of previously unmedicated birds to these compounds can cause toxicity. typically to 12 weeks of age.
Treatment
Toltrazuril. Avoid use of tiamulin in ionophore treated birds.Diagnosis
Signs. Turkey coccidiosis of the upper small intestine caused by E.

hygiene. Shuttle programmes with chemicals in the starter diet usually improve control.
35
. Caecal. Diarrhoea. mitis (see above).
Signs
      Depression.Coccidiosis. Ruffled feathers.
Diagnosis
Signs. lesions. histomonosis. Accumulation of varying quantities of blood and caseous necrotic material in the caecum. E tenella
Introduction
This was at one time the commonest type of coccidiosis and is certainly the most easily diagnosed. Morbidity is 10-40% and mortality up to 50%. Production less affected than in some of the other forms of coccidiosis. Inappetance.
Prevention
Coccidiostats in feed. Vaccines are used mainly in breeders but increasingly in broilers. Transmission as for E. E. tenella is more common when 'straight' ionophore programmes are used. blood in faeces. Closed eyes. In some markets the organic arsenical compound 3-Nitro is used as an aid in the control of caecal coccidiosis. Amprolium. Thickening. ecchymoses. Recovered birds have good immunity to the same parasite. It is caused by Eimeria tenella and results in lesions in the caecum of chickens worldwide. Differentiate from ulcerative enteritis. vaccination by controlled exposure. microscopic examination of scrapings.
Treatment
Toltrazuril. Sulphonamides. of caecal mucosa.
Post-mortem lesions
   Petechiae. Vitamins A and K in feed or water.

identification of typical small round oocysts and other stages in fresh scrapings from the small intestine. is caused by the protozoan parasite Eimeria mitis. which colonises the small intestine.
Signs
 Reduced feed conversion efficiency and weight gain. May predispose to wet litter. humidity). faeces and on fomites and birds are infected by the oral route with an incubation period of 2-5 days. The parasite is moderately resistant in the environment and highly resistant to conventional disinfectants. seen worldwide.
Post-mortem lesions
 The lesions are minimal and located in the lower small intestine (ileum) which tends to be pale and flaccid with scattered petechiae.
Coccidiosis. Predisposing factors include exposure to faeces and litter conditions that favour development of the parasite (temperature.Figure 15. The infective agent is found in litter. Moderate Eimeria tenella infection in the caecae of a chicken (Score 3). secondary bacterial enteritis.
36
.
Treatment
Not usually treated but susceptible to the products used for other forms of intestinal coccidiosis. The caecal walls are thickened and haemorrhagic and there is a mass of blood in the caecal lumen. E mitis
Introduction
This condition of chickens. The disease occurring is proportional to the amount of infective agent ingested.
Diagnosis
Mild lesions.

Ileorectal. caecum and rectum. blood in faeces. Closed eyes. vaccination by controlled exposure. E brunetti
Introduction
A relatively rare form of coccidiosis affecting chickens worldwide caused by Eimeria brunetti. extending into caecal tonsils. Oocysts in caecum and rectum. caecal coccidiosis. microscopic examination of scrapings. May be included in vaccines. This species is not usually included in vaccines for broilers. Vitamins A and K in feed or water. Ruffled feathers. Poor production.
Prevention
Coccidiostats in feed. hygiene. Sulphonamides.
Coccidiosis.
Signs
      Depression.Prevention
Normally controlled by anticoccidials in feed. Amprolium. Diarrhoea. Differentiate from ulcerative enteritis.
Post-mortem lesions
   Petechiae and thickening of the distal third or more of intestine. lesions. it is found in the terminal ileum.
Diagnosis
Signs.
37
. Inappetance. Morbidity and mortality are variable.
Treatment
Toltrazuril. Of moderate to high pathogenicity. Severe necrotising enteritis. There is good immunity to the same parasite in recovered birds.

38
.
Coccidiosis. Tyzerria has eight sporocysts in each oocyst. 3 days on). 3 days on. Amprolium. Blood-stained vent. microscopic examination of scrapings (usually few or no oocysts. Vitamins A and K in feed or water.g. Duck viral enteritis.
Diagnosis
Signs. In the goose E. of Ducks and Geese
Introduction
Young ducks and geese may suffer from Eimeria spp infection. Intestinal. anseris is the most important. Coccidiosis occurs only very rarely in commercially reared ducks in the UK. 2 days off. Tucked appearance.
Treatment
Sulphonamides (e. compared to four per oocyst forEimeria. Depression. lesions. Sulphadimidine 30-600gm/100 birds/day.
Signs
    Sudden death. There is thickening of the intestinal mucosa and there are lines of haemorrhagic spots in the mucosa.Figure 16. while in ducksTyzzeria perniciosa is most pathogenic. large number of merozoites). Moderate Eimeria brunettiinfection in the terminal ileum and rectum of a chicken. Differentiate from Duck viral hepatitis. anatipestifer.
Post-mortem lesions
 Massive haemorrhage in upper small intestine.

Kidney
Introduction
A disease of geese caused by Eimeria truncata that can cause high mortality in geese of 312 weeks of age. Diarrhoea . Kidneys light grey to greyish pink. it can also infect Barbary ducks and swans. Reduced feed intake.
Signs
    Depression.faeces tend to be whitish. Tiny white foci and petechiae in the kidneys.Prevention
If required coccidiostats could be used in feed.
Prevention
Good Hygiene.
Post-mortem lesions
   Enlarged kidneys. Weakness.
Treatment
Controlled trials of treatments have not been published. Hygiene. presence of coccidial stages in fresh scrapings of kidney lesions.
39
.
Coccidiosis.
Diagnosis
Lesions. however this is not routinely practised.

mucosa tends to be pinker than normal. vaccination. of moderate to high pathogenicity it is seen worldwide. Closed eyes.
Diagnosis
Signs. microscopic examination of scrapings. Blood or pigment in the faeces. Mid-intestinal. Differentiate from necrotic enteritis. contents often orange in colour. Vitamins A and K in feed or water.
Post-mortem lesions
    Petechiae and thickening of middle third of intestine. Morbidity and mortality are variable. Poor production.
40
. Depigmentation of skin and plasma is especially evident in this form of cocccidiosis and this is commercially important in some markets. Mild to severe enteritis. Ruffled feathers.
Signs
       Depression. non-specific enteritis. Because of the area of intestine affected it tends to have a significant effect on productivity and susceptibility to necrotic enteritis. lesions. Amprolium. commercial vaccines commonly contain more than one strain of E. This infection is often associated with E. maxima. E maxima
Introduction
One of the more common forms of coccidiosis in commercial broilers.
Treatment
Sulphonamides. This is one of the less immunogenic species.Coccidiosis. Inappetance. Poor absorption of nutrients/pigments.
Prevention
Coccidiostats in feed. Caused by Eimeria maxima. acervulina coccidiosis and there may be large numbers of characteristic oocysts in smears. hygiene.

Diagnosis
Signs. in which the parasite is present in the small intestine and in the caecum. Deep scrapings necessary to show large schizonts. Inappetance.
Post-mortem lesions
    Petechiae and thickening. of middle to posterior third or more of small intestine. Schizonts seen as white spots through the serosa interspersed with petechiae. caused by Eimeria necatrix. other types of coccidiosis. Oocyts in caecal scrapings.Figure 13. Diarrhoea. 'Sausage-like' intestine. The lesions are subtle compared to other forms of coccidiosis.
Signs
       Reduced feed consumption. The intestine is slightly thickened and there are scattered haemorrhages in the mucosa when seen from the inside. E necatrix
Introduction
A highly pathogenic form of coccidiosis. Depression. Mid-intestinal. lesions. Closed eyes. Severe necrotising enteritis.
Coccidiosis. blood in faeces. Ruffled feathers. microscopic examination of scrapings Differentiate from necrotic enteritis.
41
. Poor production. It occurs in chickens worldwide and has variable morbidity but mortality is high in severely affected birds. Moderate Eimeria maxima infection in the jejunum of a chicken (Score 2).

Inappetance. In this case the intestine is thickened and can become ballooned and sausage-like. It is seen in layers and in broilers. Closed eyes. Vitamins A and K in feed or water. Poor production. both alone and in association with other species of coccidia and is caused by Eimeria acervulina.
Prevention
Coccidiostats in feed. Sulphonamides. vaccination. Moderate Eimeria necatrix infection in the jejunum of a chicken (Score 3).Treatment
Toltrazuril. commercial vaccines commonly contain more than one strain of E.
Signs
       Depression. Haemorrhages and white spots are visible from the outside of the intestine. maxima.
Figure 14. which is moderately pathogenic. E acervulina
Introduction
This is probably the commonest cause of coccidiosis in chickens and occurs worldwide. Diarrhoea. This is one of the less immunogenic species. Upper Intestinal.
Post-mortem lesions
42
. Depigmentation. Amprolium. acervulina. Ruffled feathers. Morbidity is variable and mortality low or absent.
Coccidiosis. hygiene. Eimeria mivatiis currently considered not to be a valid species distinct from E.

lesions.
Treatment
Toltrazuril. A system of assessing the severity of coccidial challenge by attributing a 'score' is often used. in severe the entire surface is pale or denuded of epithelium. In milder infections there may be scattered white spots. In severe infections they become confluent and cause sloughing of the mucosa.the duodenum and part of the ileum.
Figure 12. Differentiate from necrotic and non-specific enteritis. vaccination by controlled exposure. Petechiae. Sulphonamides. In general terms a score of 0 indicates no lesions and a score of 4 indicates maximal severity of lesion or death. in feed or water. Immunity is quite short lived (about 30 days) in the absence of continued challenge. Moderate Eimeria acervulinainfection (score 2) in chicken duodenum. Poor absorption of nutrients/pigments. hygiene.
43
. Various publications provide a photographic key to severity of lesion. restricted to upper third of small intestine .
Prevention
Coccidiostats in feed.
Diagnosis
Signs. and other lesions.    
Thickening. microscopic exam of scrapings. White spots or bands in the mucosa. A detailed description is beyond the scope of this book. Amprolium.

mortality is 5-20%. Enteritis. Poor growth. Poor navel healing. sneezing. It is frequently associated with immunosuppressive diseases such as Infectious Bursal Disease Virus (Gumboro Disease) in chickens or Haemorrhagic Enteritis in turkeys. Arthritis. and via shell membranes/yolk/navel. Colisepticemia
Introduction
Coli-septicaemia is the commonest infectious disease of farmed poultry. Synovitis. Aerobic culture yields colonies of 2-5mm on both blood and McConkey agar after 18 hours . Lesions vary from acute to chronic in the various forms of the disease. turkeys.
Signs
      Respiratory signs. water.Colibacillosis. It is caused by the bacteriumEscherichia coli and is seen worldwide in chickens.
Diagnosis
Isolation. Morbidity varies. but is susceptible to disinfectants and to temperatures of 80°C.
Post-mortem lesions
             Airsacculitis. Infection is by the oral or inhalation routes. etc. Perihepatitis. It is most commonly seen following upper respiratory disease (such as Infectious Bronchitis) or Mycoplasmosis. Swollen liver and spleen. Omphalitis. or in young birds that are immunologically immature. Omphalitis. Cellulitis over the abdomen or in the leg.most strains are rapidly lactose-fermenting producing
44
. Salpingitis. fomites. mucosal damage due to viral infections and immunosuppression are predisposing factors. Pericarditis. sero-typing. pathology. with an incubation period of 3-5 days. The infectious agent is moderately resistant in the environment. Reduced appetite. Snick. Peritonitis. Dejection. coughing. Granulomata in liver and spleen.

Prevention
Good hygiene in handling of hatching eggs.
Figure 17. Control of predisposing factors and infections (usually by vaccination). other enterobacteria such as Proteus. Hock Burn. Contact dermatitis is commonly monitored at processing as a means of measuring 'welfare status'. Immunity is not well documented though both autogenous and commercial vaccines have been used. good sanitation of house.brick-red colonies on McConkey agar. the foot pad. The liver is almost entirely covered by a substantial layer of fibrin and pus. when severe.
45
. It is seen in growing broiler chickens and turkeys. tetracyclines. neomycin (intestinal activity only). Staphylococcus spp. stage of resolution and severity of lesion is likely to affect the degree of discomfort or pain suffered. Severe perihepatitis in colibacillosis in a broiler parent chicken. gentamycin or ceftiofur (where hatchery borne). Some lesions are superficial. as well as Pseudomonas. feed and water. hatchery hygiene. Well-nourished embryo and optimal incubation to maximise day-old viability. etc. and in broiler parents. potentiated sulphonamide. whereas others progress to deep ulcers so the size. Pododermatitis
Introduction
Contact dermatitis affects skin surfaces which have prolonged contact with litter. the breast area.
Treatment
Amoxycillin. Differentiate from acute and chronic infections with Salmonella spp. rear surface of the hock and. flouroquinolones.
Contact Dermatitis.

proper insulation in cold climates. Choice of drinker type (nipple as opposed to bell).Pododermatitis is often related to high droppings pH. stickiness of droppings). level of soya bean meal in feed (according to some authors. most importantly. and sometimes in the breast area. See the discussion in the section on Dysbacteriosis. and. and adequate ventilation to remove moisture are all important. litter moisture. Moderate pododermatitis on a foot pad.
Post-mortem lesions
 As described under signs. drinker management.
Diagnosis
Signs and lesions. If severe the foot and hock lesions may contribute to lameness or serve as a portal of entry for secondary infections.
Treatment
Not applicable.
46
. It can be reproduced by adding water to the litter. at the back of the hocks.
Prevention
This condition is closely linked to intestinal function as this is the prime determinent of faecal consistency and stickiness.
Figure 18.
Signs
 Blackened skin progressing to erosions and fibrosis on the lower surface of the foot pad.

Cryptosporidiosis
Introduction
Cryptosporidia are related to the coccidia. meleagridis also infects both species.
47
.
Post-mortem lesions
  Inflammation and thickening of mucosa of crop and oesophagus. Coumaphos.
Prevention
Effective cleaning of housing. Some have beetle or earthworms as intermediate hosts. The same species causes infections of the hindgut and cloacal bursa in chickens. acervulinaoocyst).C. Avoidance of access to intermediate hosts. and ducks. although bird strains do not infect mammals very well.
Signs
  Anaemia. and vice versa.
Treatment
Levamisole. Cryptosporidium baileyi can cause respiratory disease in chickens and turkeys. They replicate in the brush border on the surface of epithelial cells.Cropworms
Introduction
The nematode worms Capillaria spp and Gongylonema ingluvicolainfect the mucosa of the crop and oesophagous of poultry and game birds. Routine worming. White convoluted tracks in the mucosa. Emaciation. A further species causes respiratory disease in quail. The oocysts are excreted ready sporulated in the faeces and infection occurs by inhalation and ingestion.
Diagnosis
Microscopic examination of mucosal scraping. but much smaller (typically oocysts are less than ¼ of the size of an E. They also differ from coccidia in being poorly host specific. turkeys.

Pneumonia. Swollen sinuses.Signs
     Snick.
Prevention
The oocysts of cryptosporidia are extremely resistant to chemical disinfection. recumbency. Steam cleaning is effective in reducing infection as oocysts are inactivated above about 65°C
Dactylariosis
Introduction
A rare fungal disease of chickens and turkeys caused byDactylaria gallopava. Diarrhoea. It is becoming increasingly common for water companies to screen water supplies for cryptosporidia because of the human health implications of mammalian strains. If other disease processes are complicating the situation (e.
Signs
    Incoordination. Tremors. Airsacculitis.
Diagnosis
Identification of the parasites attached to the epithelium by microscopic examination (smears histopathology acid-fast staining). Cough.
Post-mortem lesions
   Sinusitis. Circling.
48
. There are no effective preventative medicines or feed additives. coli-septicaemia) there may be benefit in medicating for these. Torticollis.
Treatment
Unfortunately there is currently no known effective treatment in poultry.g. Low weight gain.

Mycotic lesions in lungs.
Prevention
Use fresh dry litter (avoid old sawdust).
Post-mortem lesions
  Damaged epiphyseal articular cartilage.
Treatment
None.
Diagnosis
Gross and microscopic lesions.
Treatment
49
. or developmental defects. Rapid growth is a possible predisposing factor.
Signs
  Lameness. but it may result from physical damage.
Degenerative Joint Disease
Introduction
A condition of chickens and turkeys seen worldwide. The cause remains to be confirmed. resulting in erosions. Microscopically there is necrosis and there may be fissures of articular cartilage and associated osteochondritis. Reduced breeding performance. Morbidity and mortality are low but affected birds are more likely to be 'picked upon' and may end up suffering damage and needing to be culled.
Diagnosis
Lesions. isolation of the fungus. especially of femoral anti-trochanter but also other leg joints.Post-mortem lesions
  Necrotic lesions with associated congestion in cerebrum. air sacs etc. and cartilage flaps.

There may be a place for growth-control programmes.
Prevention
Careful cleaning of buildings during down-time will help reduce the risk of these infections. round. Appropriate management of a segregation pen and early marketing of mildly affected birds may limit losses and improve flock welfare. pigeons etc.None available.Knemidocoptes spp. Raised thickened scales.
Prevention
Avoidance of physical sources of injury to bones and joints. pheasants.
Depluming and Scaly Leg Mites
Introduction
External parasites of adult chickens. Application of mineral or vegetable oil is also beneficial.
Diagnosis
Signs.
Signs
    Cause irritation and the bird pulls feathers.
Treatment
Not usually required in commercial poultry.
50
.5mm in diameter. It may be best to cull affected birds from small flocks. microscopic examination for mites in scrapings. The adult females are short legged. up to 0.
Post-mortem lesions
 As described under signs. Unthriftiness. Mange lesions on legs and unfeathered parts. especially during period of rapid growth. Exclusion of wild birds from chicken areas is advised as far as possible. For small flocks dipping the affected parts in a solution of acaricide may be beneficial.

Diagnosis
History and lesions. Reserpine in diet of birds of 4+ weeks (no longer licensed in the UK). pericardial sac. Skin pale. Abdominal cavity full of blood. The disease is transmitted by infected ducks and other waterfowl and spreads rapidly.
Prevention
Limit feed in birds of 16+ weeks.
Signs
   Sudden death with no warning signs. birds found on breast or side. It has been suggested that degenerative changes in the wall of the artery and copper deficiency may be factors. A sudden noise or other cause of excitement can lead to an 'outbreak'. Reserpine. presumably due to a sudden increase in blood pressure.
Duck Viral Hepatitis
Introduction
A viral disease of ducks occurring worldwide and previously a scheduled disease in UK. Haemorrhages in lungs. leg muscles. Morbidity is around 100% and mortality 0-95%. recovered birds carrying the virus for 8 weeks. a picornavirus may also
51
. The infective agent. genetic condition of turkeys linked to male sex and high growth rate. Possibly blood in the mouth. Aspirin at 250 ppm in feed or water may be of benefit.
Post-mortem lesions
     Carcase anaemic. Rupture of major blood vessel at base of heart or by the kidneys. a tranquilizer.
Treatment
None currently licensed. A longtitudinal split of the abdominal aorta is the most common lesion.Dissecting Aneurysm. was included in feed at 1 ppm for 3-5 days to reduce blood pressure. Aortic Rupture
Introduction
A complex. kidneys.

in USA since 1967. paddling of legs. Recovered birds may carry the virus for a year. SN serology. Differentiate from Duck plague (viral enteritis). isolation in CE (causes stunting of 9 day embryo). Microscopically . Depression. also the Netherlands and other countries. lesions.
Treatment
Antiserum. Punctate/diffuse haemorrhages. Live.
Post-mortem lesions
    Liver swollen. Kidneys and spleen swollen. 0. Newcastle disease. mostly in ornamental collections.focal necrosis. The disease follows a very acute course with a morbidity of 5-100% and mortality of 5-100%. only slightly attenuated vaccine is applied at day old by foot web stab and may be repeated in breeding birds to provide maternal immunity. Fall on side.
Signs
    Sudden death.
Prevention
Vaccination and/or antiserum. Death in good condition.5 ml serum of recovered birds given intramuscularly. Transmission is by infected birds.survive for ten weeks in brooders and five weeks in faeces. Influenza and a 'Type II Variant' hepatitis caused by Astrovirus.
Diagnosis
History. breeder vaccination. fomites and arthropods. bile duct proliferation and inflammation. coccidiosis.
Duck Virus Enteritis. Duck Plague
Introduction
A herpesvirus infection of ducks and geese diagnosed in the UK in 1972. arching of back. All waterfowl are susceptible and the Barbary duck is more susceptible than the Pekin. Duck septicaemia (anatipestifer).
52
. often in opisthotonus. rapid deterioration and death. A different picornavirus causes a similar condition in North America.

Argentina.
Diagnosis
Signs. Uruguay.Dietary changes. Voluminous caecae.
Egg Drop Syndrome 76
Introduction
Egg drop may be defined as a sudden drop in egg production or a failure to achieve a normal peak in production. No single bacterium appears to be responsible. Spain.
Treatment
Amoxycillin and tylosin treatment appear to be beneficial. lesions.
Post-mortem lesions
   Excessive fluid content throughout the small intestine. France.
Prevention
Competitive exclusion ('normal adult flora') use in day-old chicks reduces the risk of this condition. In the autumn of 1976 a distinct egg drop syndrome was first identified in Northern Ireland. Holland.
Signs
  Diarrhoea. first isolated in Northern Ireland in 1976. Treatment should coincide with good relittering and it is important to provide fresh sanitary drinking water. The cause has been identified as Adenovirus BC14. Prophylactic antimicrobial medication may be necessary in some circumstances. Good control of coccidiosis. Apparently a similar disease had been seen over a 4-year period in broiler parents in Holland. often with gas bubbles. 127. Careful choice of any feed enzymes and their matching with local raw materials can have an impact on substrates made available to intestinal bacteria. Germany. Peru. Water intake may be increased or irregular. Mortality is usually negligible. microscopic examination of scrapings from the wall of the small intestine (to exclude coccidiosis and perhaps to assess the bacterial flora). It affects chickens and has occurred in Ireland. feed interruptions and subclinical coccidiosis may be contributory factors. Brazil. Circumstantial evidence suggests that the main route of transmission is through the eggs (vertical transmission)
54
. England. Feed acidification may be helpful in some circumstances. especially where treatment is initiated early. rather we are dealing with a disruption in the normal flora of the gut. Wet faeces in the rectum.

and D as well as calcium. B 12. Elisa. Unvaccinated flocks with antibodies before lay do not peak normally. The infection is commonly present in ducks and geese but does not cause disease. sudden changes of feed. Lack of signs in the birds themselves. Parasites. signs/lesions (mainly lack of). inadequate lighting programme. which can be caused by a large number of factors acting individually or in combination. Rough. may be infectious or metabolic.
Diagnosis
History. Coryza. Metabolic diseases include Fatty Liver Syndrome. Drops may be of 5 to 50% and last for 3-4 weeks. extremes of temperature. as may wildfowl and biting insects. Cholera. DID.
Signs
     Egg drop at peak or failure to peak.followed by latent infection during rear with viral excretion starting shortly before sexual maturity. phosporus. Poor internal quality. specifically vitamins E.
Post-mortem lesions
  No specific lesion . Diseases in which egg drop occurs. Isolation of haemagglutinatin agent in duck eggs or cell culture. thin or soft-shelled eggs and shell-less eggs. Marek's disease/Leukosis or any infectious disease causing a significant systemic disturbance (CRD. Newcastle disease. group antigen distinct from classical adenoviruses (white cells. Clinical disease occurs during sexual maturity. insecticides or nicarbazin. Avian Encephalomyelitis. Spread from house to house may take 5-10 weeks. SN. It is important to rule out other possible reasons for egg drop. Infectious diseases include Infectious Bronchitis. Infectious Laryngotracheitis. Serology: HI. Loss of shell pigment. Diphtheritic Fowl Pox). Contamination of egg trays at packing stations may play a part in transmission.
55
.it may be possible to demonstrate degenerative changes in the epithelial cells of the magnum of the oviduct. Histopathology . selenium. Management problems may be involved: inadequate water supply.only a slight atrophy of ovary and oviduct. oviduct). intoxication by sulphonamides. Nutritional deficiency should be considered. Lateral transmission from bird to bird is slow and may be prevented or slowed for weeks by netting divisions. throat swabs.

Epiphysiolysis
Introduction
A complex condition of chickens that may be associated with trauma.
Treatment
Medication is only likely to be of value in reducing deterioration in birds that are starting to develop lesions. If successive flocks are affected on the same site prophylactic medication ahead of the anticipated problem may be of benefit.
56
. Soluble multivitamins may be recommended as a nonspecific measure. and /or trauma.
Diagnosis
Differentiate from broiler ascites syndrome by examination of the interior of the heart. Erysipelothrixetc. Peripheral vessels congested.
Prevention
Vaccination with inactivated vaccine prior to lay.Treatment
None. The choice should depend on sensitivity testing of an isolate.
Signs
  Fluid-distended abdomen.
Prevention
Good hygiene at turn-around. rickets.
Post-mortem lesions
  Right ventricular failure and ascites. Vegetative lesions usually on the right atrioventricular valve.
Endocarditis
Introduction
A condition of chickens associated with several bacterial infections such as staphylococci. bacterial infection. osteomyelitis. streptococci. growth plate disease. Culture of lesions to confirm the bacterium involved.

partridges. Paralysis.
57
. WEE. Circling. The natural hosts are wild birds and rodents. turkeys. ducks and pigeons having a high morbidity and high mortality.
Treatment
Not applicable. VEE)
Introduction
A viral disease of pheasants. Paresis. Flaccid neck. Ataxia.
Signs
        Nervous symptoms. sometimes seen in vivo.
Post-mortem lesions
  No gross lesions.
Post-mortem lesions
 Separation of epiphyses at the growth plate.Signs
 Apparent dislocation at extremities of long bones.
Equine Encephalitis (EEE. Microscopic lesions not pathognomonic. wild birds. Tremors.
Diagnosis
Gross inspection. May also be asymptomatic. These conditions currently only occur from northern South America to North America. histology may be helpful in identifying underlying problems such as rickets or 'FHN'.
Prevention
Control of predisposing factors. often occurs or is identified in the processed carcase. It is transmitted between birds by pecking and by mosquitoes. Horses are also seriously affected. chickens.

Haemorrhages in fat. It may be transmitted by faecal carriers for 41 days. Sudden death. Joint lesions. Swollen snood. Vaccinate at 5-6 week. Liver. muscle. The bacterium is fairly resistant to environmental effects or disinfectants and may persist in alkaline soil for years. COFAL. Chronic scabby skin. pheasants.
Signs
        Inappetance. especially snood. control cannibalism. in soil.
Post-mortem lesions
      Carcase congestion.
Erysipelas
Introduction
A sudden onset infection with the bacterium Erysipelothrix insidiosa (E. It is also seen in some mammals. kidney. May be diarrhoea and respiratory signs. There is likely to be an increased risk if housing or land has been previously used by pigs or sheep. rarely in geese. Marked catarrhal enteritis. rhusiopathiae) seen in turkeys and increasingly in free-range chickens.
Treatment
None.
Prevention
Protection from mosquitoes. Endocarditis. Sleepiness. Depression. fishmeal and semen and by cannibalism.
58
. water.Diagnosis
Isolation in mice. and CE. ducks. spleen swollen. Perineal congestion. epicardium. TC. ID by VN.

and identification. Tetracyclines in feed may also be helpful.
Fatty Liver Haemorrhagic Syndrome
Introduction
A condition occurring worldwide in chickens. and acute Newcastle disease. Death by internal exsanguination after rupture of haematocyst.a combination of the procaine and benzathine salts may be injected. Some birds with pale comb and wattles.
Diagnosis
Lesions.
Signs
    Overweight typically by 25%. Differentiate from pasteurellosis. the demonstration of the organism in stained impression smears from tissues. Sudden drop in egg production.
Prevention
Good biosecurity to prevent spread from other susceptible species.
Treatment
Penicillin .Diagnosis
Isolation on blood agar. Headparts pale. salmonellosis. synoviae plate tests for a few weeks. mycotoxins. often along with bacterin. colibacillosis. Sudden death. deficiency and stress. history.
Post-mortem lesions
    Obesity.
59
. vaccine at 16-20 weeks if the condition is enzootic. greasy and soft with numerous haemorrhages. especially caged layers and with a complex set of causes including excessive calories. Liver yellow. Vaccination or natural infection may cause false positive reactions in the Mycoplasma gallisepticum and M.

coli.
Prevention
Exclusion of floor eggs and dirty eggs from the hatchery. staphylococci. turkeys. (increasing order of susceptibility). Post-mortem studies of birds culled due to lameness and of birds found dead. Use of a wing for support during walking and hip flexion.75% of all male broilers placed had lesions in the hip bone.
Diagnosis
Base on post-mortem lesions and isolation of a causative organism. Predisposing factors include immunosuppresive viruses such as Infectious Bursal Disease Virus and Chicken Anaemia Virus and non-infectious bone pathologies such as hypophosphaetamic rickets.
Post-mortem lesions
 Degeneration of the epiphyses of long bones with thinning of the cortex and tendency to break when force is applied.
Signs
  Lameness.FHN
Introduction
A condition of chickens and turkeys that may be associated with several different bacterial infections e. Differentiate from synovitis.g.
Fowl Cholera. especially hypophosphataemic. arthritis. Pasteurellosis
Introduction
Fowl Cholera is a serious. spondylolisthesis. E. FHN is the commonest infectious cause of lameness in broilers in the UK.
Treatment
Antibiotic therapy in accordance with sensitivity is likely to be beneficial only for birds in the early stage of this process and may not be economically justifiable.Femoral Head Necrosis . Careful attention to mineral and Vitamin D nutrition to avoid subclinical. and water fowl. highly contagious disease caused by the bacterium Pasteurella multocida in a range of avian species including chickens. It is seen worldwide and was one of the first infectious
61
. indicated that 0. streptococci. rickets.

The disease can range from acute septicaemia to chronic and localised infections and the morbidity and mortality may be up to 100%. ocular and oral discharge.
Treatment
Sulphonamides. Differentiate from Erysipelas. faeces. or limited to haemorrhages at few sites. by Louis Pasteur in 1880. septicaemic viral and other bacterial diseases. Predisposing factors include high density and concurrent infections such as respiratory viruses. Ruffled feathers. tetracyclines. Lameness. but may persist for prolonged periods in soil. The route of infection is oral or nasal with transmission via nasal exudate.no growth on McConkey). The incubation period is usually 5-8 days. necessitating long-term or periodic medication. erythromycin. Swollen and cyanotic wattles and face. equipment. Diarrhoea. Focal hepatitis. Coughing. confirmed with biochemical tests.
Signs
          Dejection. contaminated soil.
Post-mortem lesions
        Sometimes none. The bacterium is easily destroyed by environmental factors and disinfectants. Lungs with a consolidated pink 'cooked' appearance in turkeys. Enteritis. penicillin.diseases to be recognised. isolation (aerobic culture on trypticase soy or blood agar yields colonies up to 3mm in 24 hours . and possibly pigs. Swollen joints. Yolk peritonitis.
Diagnosis
Impression smears.
62
. Cellulitis of face and wattles. and people. Purulent pneumonia (especially turkeys). Purulent arthritis. The disease often recurs after medication is stopped. Nasal. streptomycin. Loss of appetite. Sudden death. cats. Reservoirs of infection may be present in other species such as rodents.

good rodent control. It is more common in males because of their tendency to fight and cause skin damage. Depression.
Signs
      Warty. spreading eruptions and scabs on comb and wattles. live oral vaccine at 6 weeks. Caseous deposits in mouth. and where there are biting insects. hygiene. and mosquitoes (infected for 6 weeks). It is transmitted by birds.
63
. Poor growth. throat and sometimes trachea. The swelling is made up of oedema and purulent exudates (pus). 0-50%. Severe localised Pasteurella infection in the swollen wattle of a 30-week-old male broiler parent chicken. turkeys. pigeons and canaries worldwide. bacterins at 8 and 12 weeks.Prevention
Biosecurity.
Fowl Pox. Poor egg production. The duration of the disease is about 14 days on an individual bird basis. Pox. Inappetance. fomites. Infection occurs through skin abrasions and bites. Avian Pox
Introduction
A relatively slow-spreading viral disease characterised by skin lesions and/or plaques in the pharynx and affecting chickens. Morbidity is 1095% and mortality usually low to moderate. or by the respiratory route. The virus persists in the environment for months.
Figure 19.

There is good cross-immunity among the different viral strains. Turkeys by thigh-stick at 2-3 months.
Treatment
None. Chickens well before production. be caseous plaques in mouth.
Figure 20. isolation (pocks on CE CAM) with IC inclusions. reproduction in susceptible birds. trachea and/or nasal cavities. It is confirmed by IC inclusions in sections/ scrapings. If there is evidence of secondary bacterial infection broad-spectrum antibiotics may be of some benefit.intra-cytoplasmic inclusions (Bollinger bodies) with elementary bodies (Borrel bodies). Less commonly there may. check take at 7-10 days post vaccination.
64
.
Diagnosis
A presumptive diagnosis may be made on history. signs and post-mortem lesions.Post-mortem lesions
   Papules progressing to vesicles then pustules and scabs with distribution described above. Differentiate from Trichomoniasis or physical damage to skin. DNA probes. Flocks and individuals still unaffected may be vaccinated. Fowl pox lesions on the wattle of an adult broiler parent chicken. in the diptheritic form. pharynx. usually with chicken strain by wing web puncture.
Prevention
By vaccination (except canary). Microscopically .

paired parasites up to 2 cm long. Loss of appetite and condition. Head shaking. pheasants.
Gape
Introduction
Syngamus trachea. levamisole.Figure 21. a nematode worm parasite of chickens.g. Infection is by the oral route with earthworms.
66
. confirmation of presence of the parasite.
Prevention
Flubendazole.
Signs
    Gasping. slugs and snails acting as transfer hosts but the life cycle may also be direct. Presence of worms. Dyspnoea. by ingestion of embryonated egg or L3.
Diagnosis
Signs and lesions.
Post-mortem lesions
  Tracheitis. There is an 18-20 day prepatent period. Severe gangrenous dermatitis on the upper surface of the wing of a broiler chicken. turkeys. The condition is seen more commonly in poultry on free range where ground may be contaminated by wild birds e.
Treatment
Flubendazole in feed. from rookeries. and other game and ornamental birds occurring worldwide.

Geese
Introduction
A nematode worm parasite. Cheilospirura and Streptocara are seen worldwide but Histiocephalus is restricted to Europe.Gizzard worms .
Gizzard worms . routine worming.
67
.
Treatment
Levamisole.
Post-mortem lesions
  Ulceration. Grasshoppers.
Diagnosis
Lesions. Slow growth. They are more common in free-range birds because of their increased access to intermediate hosts. Adults are 2-4 cm long and usually bright red. Loss in condition and weight.Chickens
Introduction
Cheilospirura. affecting geese and ducks.
Signs
   Depression. Amidostomum anseris. necrosis and partial sloughing of gizzard lining. Loss in condition and weight. weevils. beetles etc act as intermediate hosts. confirmation of presence of the worms.
Signs
   Depression. Slow growth. Streptocara. muscular wall may be sacculated or ruptured. Worms develop to L3 in eggs and infection is by the oral route direct from environment. and Histiocephalus are nematode worm parasites of chickens. benzimidazoles such as flubendazole.
Prevention
Prevention of access to intermediate hosts.

Vertical transmission resulting in congenital infection may occur. muscular wall may be sacculated or ruptured. Reddening of skin. spleen and pancreas.
Treatment
Levamisole. Losses are negligible in birds over 5 weeks of age.Post-mortem lesions
  Ulceration. Derzsy's Disease is caused by a parvovirus distinct from chicken and mammalian parvoviruses.
Prevention
Rotation of ground on annual basis. Membrane covering tongue. The younger the bird affected the more acute the condition and the higher the mortality. Adults are 2-4 cm long and usually bright red. necrosis and partial sloughing of gizzard lining.
Signs
        Prostration and death in acutely affected goslings. Profuse white diarrhoea. visualisation of worms. Loss of down.
Diagnosis
Lesions.
Post-mortem lesions
  Pale myocardium. Swollen eyelids and eye and nasal discharge. Swelling and congestion of liver. benzimidazoles.
68
. Reduced feed intake. The amount of maternal antibody passed from the breeding birds will affect the severity and timing and severity of the condition in the young birds.
Goose Parvovirus (Derzsy's Disease)
Introduction
Goose Parvovirus is a highly contagious condition of geese and young Muscovy ducks. Excessive water intake.

Bone marrow pale with fatty change.
Prevention
Hatching and brooding geese from different parent flocks together should be avoided. Haemorrhagic Anaemia
Introduction
A complex condition of chickens associated with drug toxicities.
Signs
     Dejection. muscles. liver. Carcase anaemia. serosa and mucosae. mortality is 5-50%. Fibrinous perihepatitis.
Treatment
No specific treatment. heart.
Haemorrhagic Disease. Liver yellow. Loss of appetite.
Diagnosis
Signs and lesions in birds of the appropriate age and species. Pale comb and wattles. The preferred approach is to immunise breeding birds with an attenuated live vaccine. Poor growth. mycotoxins and viral infections and usually following a course of approximately 3 weeks. Blood in droppings. Administration of immune serum has been shown to be effective but may require two doses (day old and around 3 weeks).  
Fibrinous pericarditis.
69
. Morbidity varies. Ideally flocks that have suffered the disease should not be used for breeding as they may become persistent excreters of the infection. Ascites. Aplastic Anaemia. Antimicrobials may be of value in reducing the effects of secondary bacterial infections.
Post-mortem lesions
    Haemorrhages in one or more sites: skin.

Ducks are relatively resistant to heat stress. and turkeys caused by high environmental temperature.
Prevention
All-in/all-out production. Increased thirst. Maternal antibody may interfere with vaccination. convalescent serum.
Heat Stress
Introduction
A condition seen in chickens. In this case a loop of intestine has been opened to show the blood. good management. Pathogenic strains can depress both B.
Signs
   Panting. oral tetraycline. drinking water temperature and availability. Live vaccines are commonly used in many countries at 4-5 weeks of age.
Figure 39. high stocking density. especially associated with high relative humidity and low air speed. nicarbazin in feed.and T-line lymphocytes for up to 5 weeks following exposure. Predisposing factors include genetics. good hygiene and biosecurity.
71
. Immunity to the disease is long lasting. Disinfect and 3-4 weeks house rest. feather cover.Treatment
Warmth and good management. Turkeys dying with haemorrhagic enteritis commonly have the small intestine distended with blood. Immunity: there is an early age resistance irrespective of maternal antibody status. some in turkey B-lymphoblastoid cell lines. Some are produced in live turkeys. acclimation. Reduced feed consumption.

Caecal tonsils congested. paratyphoid. The effect of antibiotic may be related to the control of secondary bacterial enteritis. The problem is seen in high-biosecurity facilities. hygiene. It has recently been demonstrated that infection occurs readily via the cloaca when birds are on contaminated litter. and also. and mixing groups of different ages. Poor growth.
Signs
       Depression. Outwith earth worms orH. Cyanosis of head. 
First half of intestine inflamed. Within a turkey shed transmission is rapid in spite of the fact that it is difficult to infect birds orally with unprotected parasites. Although chickens are relatively resistant to the condition. Inappetance. gallinae the parasite is easily destroyed. if possible. significant disease has been seen in breeding chickens and free-range layers. dimetridazole and ipronidazole have been used in the past.
Prevention
Depopulation. presumably introduced with worm eggs. histomonosis. pheasants and game birds that acts together with facultative bacteria to produce the condition of Blackhead. This condition has high morbidity and mortality in turkeys. dimetridazole.
Diagnosis
Lesions. Blackhead
Introduction
Histomonas melagridis is a protozoan parasite of turkeys. scrapings from fresh material. Blood in faeces (chickens). Sulphur-yellow diarrhoea. The parasite is ingested in the ova ofHeterakis worms or as larvae in earthworms or faeces and there is an incubation period of 15-20 days. Differentiate from transmissible enteritis.
73
. all-in/all-out production. Progressive depression and emaciation. Histomoniasis. trichomoniasis. increase ambient temperature. avoid interspecies mixing.
Treatment
Tetracycline. Furazolidone. and occasionally chickens.
Histamonosis.

Liver may have irregular-round depressed lesions. It affects mainly broilers and broiler parents in rear and has also been seen in pigeons.g.Tahir
Post-mortem lesions
   Enlargement of caeca. Mortality may reach 60% but more typically 10-30%. especially in chickens.
74
. It is a condition caused by an adenovirus.g.
Treatment
Historically nitro-imidazoles (e.
Diagnosis
Lesions. Angara Disease
Introduction
This condition was first identified in broilers in Pakistan in 1987. avoid mixing species. and only nitarsone is approved in the USA. grey or green areas. caseous cores with yellow. Some herbal products based on the essential oils (e. Intensive relittering may help reduce the level of infection. nitrofurans (e. It spread rapidly in broiler producing areas in that country and the same or a very similar condition has been seen in North and South America. furazolidone.M.Abubakar. however they may not be present in the early stages. Arsenicals are less effective in treatment than they are in prevention. scrapings from fresh material. Ulcers. At the time of writing no products of these groups are approved for use in the European Union. possibly in combination with an RNA virus and immunosuppression caused by Chick Anaemia Virus or Infectious Bursal Disease. nifursol) and arsenicals (e. 'Herban)' have been used with some apparent success though controlled trials and formal approval for this purpose are not recorded. usually grey in colour. The disease is readily reproduced by inoculating birds with a bacteria-free filtrate of a liver extract from an affected bird. Regular worming to help control the intermediate hosts.nitarsone) have been used to treat this important disease of poultry. dimetridazole). given recent new knowledge on the mechanism of transmission. Use of an anti-histomonas product in feed where such products are approved but due care with respect to residue avoidance would be required. Having both chickens and turkeys on the same property is likely to increase the risk of this disease in turkeys.
Prevention
Good sanitation.g.
Hydropericardium-Hepatitis Syndrome.g. concrete floors.

Lungs oedematous. string etc.
Post-mortem lesions
    Excessive straw-coloured fluid distending the pericardium (up to 10 mls). however if young chicks to do not begin to eat feed properly they often consume litter instead. treatment of drinking water with 0. Control of predisposing immunosuppressive diseases may help limit losses. This condition usually affects only a small number of birds. and birds of any age can
75
.
Treatment
None. Good water sanitation (e.Signs
    Sudden increase in mortality. Congestion of the carcase. grass.
Diagnosis
Lesions. Formalin-inactivated oil adjuvant vaccines are reported to be highly effective and are used in areas where the condition is endemic. Lethargy. The normal function of the gizzard is to aid in the physical grinding of food materials.5% iodophor solution) appears to be beneficial.1% of a 2. pale friable liver and kidney.
Prevention
The condition typically occurs in areas of high poultry density where multi-age operation is traditional. Grit would not be classed as a foreign body.
Impaction and Foreign Bodies of Gizzard
Introduction
The gizzard or crop may become impacted with litter. Yellow mucoid droppings. histopathology. virology. to reduce their particle size to aid digestion. Huddling with ruffled feathers. Older birds ingest grit to facilitate the grinding activity in the gizzard.g. Most young commercial poultry consume feeds that have a small particle size. however sometimes free-range poultry consume large stones. Gizzard activity also acts as a pacemaker of intestinal activity and controls the speed at which food is passed to the small intestine. Impacted gizzards are then found in 'non-starter' type chicks or poults. Enlarged.

This usually happens after maintenance activities have been carred out in the housing. often with severe anaemia.
Post-mortem lesions
   The gizzard is more firm than normal and. Sweep floors after maintenance activities to remove nails and other potentially dangerous foreign bodies.
76
.consume nails.
Prevention
Good brooding management to encourage early adaptation to the diet and adequate consumption of feed and water. The disease was first described in the USA in 1963 and has also been reported in Canada. Australia. A foreign body may be found in the interior of the gizzard. caused by an adenovirus. the UK.
Inclusion Body Hepatitis
Introduction
A disease of chickens characterised by acute mortality. This may extend into the proventriculus and on into the duodeunum.
Signs
  Reduced feed intake. It allows us to confirm the proportion of chicks consuming feed and can give inexperienced poultry keepers feedback on the effectiveness of their brooding management. Italy. Nails commonly penetrate the lining of the gizzard. A number of different sero-types have been isolated from disease outbreaks but they may also be isolated from healthy chickens. and on opening is found to contain a mass of fibrous material. France and Ireland.
Diagnosis
Lesions.
Treatment
None effective in young birds. Infected birds remain carriers for a few weeks. Obvious non-starters should be culled in this situation. staples etc. Daily monitoring of the crop-fill is a useful procedure. It has a course of 9.15 days with a morbidity of 1-10% and a mortality of 1-10%. Reduced weight gain. and may penetrate the body wall.

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. Kidneys and bone marrow pale. perhaps because they have lower levels of maternal antibody. Inappetance. Formaldehyde and iodides work better. Bursa and spleen small. Ruffled feathers. Since adenoviruses are commonly found in healthy poultry. Immunosuppression. Progeny of high health status breeding flocks appear to be at greater risk. chloroform. but on the other hand many field cases show eosinophilic inclusions that do not appear to have adenovirus particles. Serology: DID for group antigen. may be important. Soluble multivitamins may help with the recovery process.basophilic intranuclear inclusions. CEL). Pallor of comb and wattles. vibrionic hepatitis.
Diagnosis
A presumptive diagnosis may be made on history and lesions. for instance due to early IBD challenge or congenital CAV infection. Blood thin. pH). Infectious Bursal Disease.Transmission may be vertical or lateral and may involve fomites. SN for individual sero-types.
Treatment
None. Curiously.
Signs
    Depression. The virus is generally resistant to disinfectants (ether. yellow. and deficiency of vitamin B12. and high temperatures. isolation alone does not confirm that they are the cause of a particular problem.
Post-mortem lesions
     Liver swollen. mottled with petechiae and ecchymoses. sulphonamide intoxication. Confirmation is made on finding inclusions in the liver. many different sero-types have been isolated from different cases. A form of the disease affecting birds under 3 weeks of age in Australia has been reproduced with serotype 8 adenovirus. Differentiate from Chick anaemia syndrome. The virus grows well in tissue culture (CEK. Microscopically . fatty liver syndrome.

E. Typing by haemagglutination-inhibition is also used. Newcastle disease). prevention of immunosuppression. About eight sero-groups are recognised by sero-neutralization. Caseous plugs in bronchi. Loss of appetite. was first described in the USA (N. disinfectants (Formal 1% for 3 mins). fomites or aerosol. is sensitive to solvents. 1931). Wet litter.
Signs
       Depression. Tracheal oedema. Morbidity may vary 50-100% and mortality 0-25%. Kidneys and bronchi may be swollen and they and the ureters may have urates. coli. probably the commonest respiratory disease of chickens. Coughing. Poor ventilation and high density are predisposing factors. These differences are due to structural differences in the spike proteins (S1 fraction). the age of the bird. which may survive 4 weeks in premises. Diarrhoea. IB
Introduction
This infection. Some birds/viral strains can be carriers to 1 year. Diuresis. The virus.
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. new sero-types continue to emerge. The cause is a Coronavirus that is antigenically highly variable. gasping. dyspnoea. Huddling. Airsacculitis.Prevention
Quarantine and good sanitary precautions. and complicating infections (Mycoplasma. Its affects vary with: the virulence of the virus. Tracheitis. The infection is highly contagious and spreads rapidly by contact. Infection is via the conjunctiva or upper respiratory tract with an incubation period of 18-36 hours. heat (56°C for 15 mins).
Infectious Bronchitis. depending on secondary infections. prior vaccination.
Post-mortem lesions
      Mild to moderate respiratory tract inflammation. alkalis. maternal immunity (young birds). Dakota.

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. Some birds/viral strains can be carriers for up to 1 year. which may survive 4 weeks in premises.
Signs
   Sudden death. The virus. fomites or aerosol.antibiotics to control secondary colibacillosis (q. disinfectants (Formal 1% for 3 mins).
Prevention
Live vaccines of appropriate sero-type and attenuation. lesions and serology. The infection spreads rapidly by contact. SN (type specific). Cellmediated immunity may also be important. depending on secondary infections.
Infectious Bronchitis. Otherwise as for standard IB.
Treatment
Sodium salicylate 1gm/litre (acute phase) where permitted . Definitive diagnosis is based on viral isolation after 3-5 passages in chick embryo. Serology: HI. Avian Influenza and Laryngotracheitis. vaccinal reactions. Muscular shivering. is sensitive to solvents. HA negative. Differentiate from Newcastle disease (lentogenic and mesogenic forms). alkalis.v. mycoplasmosis. short duration. DID (poor sensitivity.). IB . Infection is via the conjunctiva or upper respiratory tract with an incubation period of 18-36 hours. Elisa (both group specific).793b Variant Sudden Death Syndrome in Broiler Parents
Introduction
A Coronavirus infection of chickens with a morbidity of 50-100% and a mortality 0-25%. Local immunity is first line of defence. flourescent antibody positive and ciliostasis in tracheal organ culture.Diagnosis
Tentative diagnosis is based on clinical sgns. heat (56°C for 15 mins). group specific). Maternal immunity provides protection for 2-3 weeks. with typical lesions. Humoral immunity appears 10-14 days post vaccination. possible reactions depending on virulence and particle size. Poor ventilation and high density are predisposing factors.

cell culture (Vero. SN (type specific). In layers the ovules may be intensely congested. The condition has a morbidity of 10-100% and mortality of 0-1%. sneezing. IB Egg-layers
Introduction
A Coronavirus infection of chickens. Soft-shelled eggs.antibiotics to control secondary colibacillosis (q.
Prevention
Live vaccines of appropriate sero-type and attenuation. lesions progress to necrosis and scarring of deep pectorals in convalescence. Poor ventilation and high density are predisposing factors. group specific). Rales may or may not be present. possible reactions depending on virulence and particle size. There is rapid spread by contact. CK) only after adaptation Serology: HI.).v. DID (poor sensitivity.
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. Coughing. Infection is via the conjunctiva or upper respiratory tract. with much antigenic variation.
Infectious Bronchitis. ciliostatic in tracheal organ culture. Rough shells. The virus is moderately resistant and may survive 4 weeks in premises.
Treatment
Sodium salicylate 1gm/litre (acute phase) where permitted . A few birds are carriers up to 49 days post infection. Elisa (both group specific).
Diagnosis
3-5 passages in CE allantoic cavity. typical lesions.
Signs
      Drop in egg production (20-50%). Loss of internal egg quality. Other lesions of 'classical' IB may be encountered. fomites or aerosol. short duration. FA.Post-mortem lesions
   Oedema of pectoral muscles and subcutaneously on abdomen. HA-.

Infectious Bronchitis.
Prevention
Live vaccines of appropriate sero-type and attenuation.
Treatment
Sodium salicylate 1gm/litre (acute phase) where permitted . Infection is via the conjunctiva or upper respiratory tract. particle size (if sprayed) and general health status. Loss of internal egg quality.
Signs
      Drop in egg production (20-50%). FA. virulence. Differentiate from Egg Drop Syndrome.v. Elisa. Cell-mediated immunity may also be important. EDS76. Coughing. Poor ventilation and high density are predisposing factors. although reactions can occur depending on prior immunity. IB Egg-layers
Introduction
A Coronavirus infection of chickens.
Diagnosis
3-5 passages in CE. The virus is moderately resistant and may survive 4 weeks in premises. sneezing. Serology: HI. DID. Rough shells. Rales may or may not be present. fomites or aerosol.
Post-mortem lesions
  Follicles flaccid. Maternal immunity provides protection for 2-3 weeks. There is rapid spread by contact. Soft-shelled eggs. typical lesions. HA-.antibiotics to control secondary colibacillosis (q.).
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. Yolk in peritoneal cavity (non-specific). Local immunity is the first line of defence. SN. with much antigenic variation. The condition has a morbidity of 10-100% and mortality of 0-1%. A few birds are carriers up to 49 days post infection. Humoral immunity appears 10-14 days post vaccination.

the damage caused to the immune system interacts with other pathogens to cause significant effects. IBD.
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. seen worldwide. The infective agent is a Birnavirus (Birnaviridae). which targets the bursal component of the immune system of chickens. but may be via the conjunctiva or respiratory tract. Subclinical infection in young chicks results in: deficient immunological response to Newcastle disease. persisting for months in houses. first identified in the USA in 1962. faeces etc. Sero-type 1 only. with an incubation period of 2-3 days. Signs are most pronounced in birds of 4-6 weeks and White Leghorns are more susceptible than broilers and brown-egg layers.Figure 22. especially with sero-type 2). (Turkeys and ducks show infection only. The virus is very resistant. In addition to the direct economic effects of the clinical disease. susceptibility to Inclusion Body Hepatitis and gangrenous dermatitis and increased susceptibility to CRD. There is no vertical transmission. The disease is highly contagious. The age up to which infection can cause serious immunosuppression varies between 14 and 28 days according to the antigen in question.20% but sometimes up to 60%. Marek's disease and Infectious Bronchitis. Mealworms and litter mites may harbour the virus for 8 weeks. Gumboro
Introduction
A viral disease. and affected birds excrete large amounts of virus for about 2 weeks post infection. Morbidity is high with a mortality usually 0. Flaccid ovarian follicles in a broiler parent chicken undergoing challenge with Infectious Bronchitis virus. Generally speaking the earlier the damage occurs the more severe the effects.
Infectious Bursal Disease. The route of infection is usually oral.

Elisa vaccination date prediction < 7 days). IBD viruses have been isolated and shown to have significant but not complete cross-protection.
Treatment
No specific treatment is available.History. Tests used are mainly Elisa. Haemorrhages in skeletal muscle (especially on thighs).
Post-mortem lesions
    Oedematous bursa (may be slightly enlarged. Differentiate clinical disease from: Infectious bronchitis (renal). Vaccination date prediction uses sera taken at day old and a mathematical formula to estimate the age when a target titre appropriate to vaccination will occur.A history of chicks with very low levels of maternal antibody (Fewer than 80% positive in the immunodifusion test at day old.5. Huddling under equipment. Half-life of maternally derived antibodies is 3. Inappetance. lesions. Antibiotic medication may be indicated if secondary bacterial infection occurs.
84
.4 days.1% are highly suggestive. Diarrhoea with urates in mucus. Cryptosporidiosis of the bursa (rare). histopathology. The normal weight of the bursa in broilers is about 0. (previously SN and DID). Subclinical disease . Swollen kidneys with urates. Haemorrhagic syndrome. Coccidiosis. Dehydration. may have haemorrhages.Signs
      Depression.
Diagnosis
Clinical disease . Use of a multivitamin supplement and facilitating access to water may help. Vent pecking. weights below 0.3% of bodyweight. especially in the Delmarva Peninsula in the USA. Unsteady gait. This may be confirmed by demonstrating severe atrophy of the bursa. normal size or reduced in size depending on the stage). Serology: antibodies can be detected as early as 4-7 days after infection and these last for life. especially if present prior to 20 days of age. Variants: There have been serious problems with early Gumboro disease in chicks with maternal immunity. They are all serotype 1. subsequent diagnosis of 'immunosuppression diseases' (especially inclusion body hepatitis and gangrenous dermatitis) is highly suggestive. Other possible causes of early immunosuppression are severe mycotoxicosis and managment problems leading to severe stress. rapidly proceeds to atrophy.

the rectum and the vent.
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. characterised by catarrhal inflammation of the upper respiratory tract. Morbidity is high but mortality low if uncomplicated although it may be up to 20%. turgid and oedematous. This shows the anatomical relationship between the bursa. highly infectious disease of chickens. When outbreaks do occur. sometimes chronic. A strong immunity follows field challenge. including passive protection via breeders. occasionally pheasants and guinea-fowl. It is enlarged. Infectious Coryza is caused by the bacterium Haemophilus paragallinarum and is seen in many countries especially in multi-age farms that are never depopulated. and tracing of contacts may indicate sites on which a more rebust vaccination programme is indicated. It is not egg transmitted.Prevention
Vaccination. vaccination of progeny depending on virulence and age of challenge. Carriers are important with transmission via exudates and by direct contact. In most countries breeders are immunised with a live vaccine at 6-8 weeks of age and then re-vaccinated with an oil-based inactivated vaccine at 18 weeks. biosecurity measures may be helpful in limiting the spread between sites.
Figure 23. This bursa is from an acutely affected broiler.
Infectious Coryza
Introduction
A usually acute. especially nasal and sinus mucosae. Immunity after a live vaccine can be poor if maternal antibody was still high at the time of vaccination. The route of infection is conjunctival or nasal with an incubation period of 1-3 days followed by rapid onset of disease over a 2-3 day period with the whole flock affected within 10 days. resulting in increased culling.

DID. Commercial bacterins may not fully protect against all field strains but reduce the severity of reactions. Inappetance.The bacterium survives 2-3 days outside the bird but is easily killed by heat.
Prevention
Stock coryza-free birds on an all-in/all-out production policy. Confirmation is by isolation and identification .
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. Swollen wattles.
Post-mortem lesions
     Catarrhal inflammation of nasal passages and sinuses. Eye-lid adherence. Loss in condition. erythromycin. preferably in raised CO 2 such as a candle jar. Dyspnoea. while bacterins only protect against homologous strains. lesions. Birds recovered from challenge of one serotype are resistant to others. Caseous material in conjunctiva/sinus. Tracheitis. Serology: HI. identification of the bacteria in a Gram-stained smear from sinus.requires X (Haematin) and V (NAD) factors.
Treatment
Streptomycin. Bacterin at intervals if history justifies or if multi-age. chronic or localised pasteurellosis and vitamin A deficiency. agglutination and IF have all been used but are not routine. at least two doses are required. Differentiate from Mycoplasmosis.
Diagnosis
A presumptive diagnosis may be made on signs. respiratory viruses. Sneezing. Flouroquinolones are bactericidal and might prevent carriers. tylosin. Drop in egg production of 10-40%. Controlled exposure has also been practised. sulphonamides. drying and disinfectants. Dihydrostreptomycin. Live attenutated strains have been used but are more risky. Purulent ocular and nasal discharge. Vaccines are used in areas of high incidence. Conjunctivitis. Intercurrent respiratory viral and bacterial infections are predisposing factors.
Signs
        Facial swelling.

Ocular discharge. ILT
Introduction
A herpesvirus (pathogenicity can vary) infection of chickens. Coughing of mucus and blood. Keep susceptible stock separate from vaccinated or recovered birds. severe bronchitis. Differentiate from Newcastle disease. Transmission between farms can occur by airborne particles or fomites.
Post-mortem lesions
  Severe laryngotracheitis. Isolation in CE CAMs. Gasping. lesions. in severe form may be enough.Infectious Laryngotracheitis. PCR. Fairly slow lateral spread occurs in houses. The route of infection is via upper respiratory tract and conjunctiva or possibly oral and the course of the disease is up to 6 weeks. The virus is highly resistant outside host but is susceptible to disinfectants. antibiotics to control secondary bacterial infection if this is marked. Apply strict biosecurity in moving equipment or materials between these these categories of stock.
Diagnosis
Signs. after 4 weeks of age.intranuclear inclusions in tracheal epithelium. IFA. if enzootic or epizootic in an area.
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. Sinusitis. Microscopically . pheasants. Movement and mixing of stock and reaching point of lay are predisposing factors. Drop in egg production. All-in/allout operation. peafowl and turkeys with a morbidity of 50-100% and a mortality usually 10-20% but sometimes up to 70%.
Prevention
Quarantine.
Treatment
None. often with blood in lumen. Nasal discharge (low pathogenicity strains). Sera may be examined by VN or Elisa. vaccination. histology. Recovered and vaccinated birds are long-term carriers.
Signs
       Dyspnoea. caseous plugs may be present.

it may actually protrude at the vent and be cannibalised.
Leukocytozoonosis
Introduction
Caused by Leucocytozoon species. worms and other forms of enteritis are predisposing factors. Thirst. usually in the lower small intestine. Coccidiosis.
Diagnosis
Typical post-mortem lesions
Treatment
As appropriate for the underlying disease condition. The disease has a short course and morbidity and mortality are high.Intussusception
Introduction
A condition of chickens associated with increased intestinal motility. rarely chickens.
88
. Survivors may carry infection.
Prevention
Control of coccidiosis and other causes of intestinal inflammation.
Post-mortem lesions
 Telescoping of the bowel. Rapid breathing.
Signs
 Mainly sudden deaths. Simulid flies or culicoid midges are intermediate hosts. Loss of equilibrium. Asia and Africa.
Signs
     Sudden onset of depression. Anorexia. guinea fowl. Different species of this parasite have been reported from North America. ducks. protozoan parasites of turkeys. Careful attention to feeding practices to avoid anticipation of feed arrival if on restricted feeding.

Post-mortem lesions
    Enteritis.
Treatment
Daily cull of affected birds between 14 and 28 days. Diarrhoea. Runting (permanent).
Diagnosis
Pathology. Pot-bellied appearance. reoviruses.
Signs
        Uneven growth. Runting/Stunting
Introduction
A condition of chickens and turkeys that may be associated with several different viruses.(maize-) fed birds (often associated with orange intestinal contents and/or faeces). The condition has been seen in Europe. for example enteroviruses. It is suspected that these viruses can be vertically transmitted and the most severe signs in young birds are associated with this. Pale shanks in corn. Pancreatic atrophy/fibrosis and pancreatic atrophy (rather variable). Stunting (temporary). North and South America and Australia.M. temperature control) may lead to a similar picture in the absence of specific infection.
Malabsorption Syndrome. Eating faeces. Diarrhoea in older birds may be an effect of on-farm infection. enterovirus-like particles. rotavirus etc. Abnormal feathers ('helicopter wings' 'yellow-heads').
Prevention
Good hygiene.Tahir
None.Abubakar. Poor feathering. in future eradication. control arthropods. all-in/all-out production.
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. Poor management may contribute to the problem. Poor early management (feed and water supply. direct electron microscope examination of intestinal contents. Sometimes osteomyelitis and/or rickets.

Figure 24.Acute infiltration of the CNS and nerves resulting in 'floppy broiler syndrome' and transient paralysis. good parent nutrition and egg selection and santitation.Tumours in heart.Prevention
Good broiler farm hygiene. b) Visceral . lungs. The disease has various manifestations: a) Neurological . Morbidity is 10-50% and mortality up to 100%. From the 1980s and 1990s highly virulent strains have become a problem in North America and Europe. Mortality in an affected flock typically continues at a moderate or high rate for quite a few weeks. avoidance of intercurrent disease and management problems (such as chilling). tests. ovary.Tumours of feather follicles. The virus survives at ambient temperature for a long time (65 weeks) when cell associated
91
. seen worldwide. muscles.
Marek's disease
Introduction
Marek's disease is a Herpes virus infection of chickens. c) Cutaneous . fomites. as well as more longstanding paralysis of legs or wings and eye lesions. and rarely turkeys in close association with chickens. Infected birds remain viraemic for life. In 'late' Marek's the mortality can extend to 40 weeks of age. They are distended with poorly digested feed. etc. Intestines of a young broiler chick suffering from malabsorption syndrome.poorly digested food enclosed in mucus. A sample of the faeces produced is shown at the bottom of the picture . both parasitic and bacterial. Affected birds are more susceptible to other diseases. Vertical transmission is not considered to be important. The route of infection is usually respiratory and the disease is highly contagious being spread by infective feather-follicle dander.

M.. Vision impairment.
Treatment
None. pigeons and other wild birds. Skin around feather follicles raised and roughened. heart. wings and neck. histopathology. Chronic Respiratory Disease .Chicken
Introduction
Infection with Mycoplasma gallisepticum is associated with slow onset. vaccination generally with 1500 PFU of HVT at day old (but increasingly by in-ovo application at transfer). Loss of weight.
Diagnosis
History. resistant strains. Ducks and geese can
92
.
Signs
     Paralysis of legs. Microscopically . clinical signs.lymphoid infiltration is polymorphic. botulism. deficiency of thiamine. Grey iris or irregular pupil.and is resistant to some disinfectants (quaternary ammonium and phenol). especially at the start of lay. gonads.
Mycoplasma gallisepticum infection.
Post-mortem lesions
   Grey-white foci of neoplastic tissue in liver. kidney. It is common practice to use combinations of the different vaccine types in an effort to broaden the protection achieved.g. It is inactivated rapidly when frozen and thawed. spleen. all-in/all-out production. Thickening of nerve trunks and loss of striation. distribution of lesions. lung.
Prevention
Hygiene. game birds. and skeletal muscle. Genetics can help by increasing the frequency of the B21 gene that confers increased resistance to Marek's disease challenge. deficiency of Ca/Phosphorus/Vitamin D. chronic respiratory disease in chickens. Differentiate from Lymphoid leukosis. age affected. turkeys. association with other strains (SB1 Sero-type 2) and Rispen's.

Leg problems. Haemophilus. Inappetance. airborne dust and feathers. sinuses. subsequent stress may cause recurrence of disease.become infected when held with infected chickens. Transmission may be transovarian. morbidity may be minimal and mortality varies. Pericarditis. Fomites appear to a significant factor in transmission between farms. Suspect colonies may be identified by immuno-flourescence. Poor productivity. though in some countries this infection is now rare in commercial poultry.
Diagnosis
Lesions. more commonly in Mycoplasma Broth followed by plating out on Mycoplasma Agar. Slow growth. coli. Stunting. The route of infection is via the conjunctiva or upper respiratory tract with an incubation period of 6-10 days. The condition occurs worldwide. Perihepatitis (especially with secondary E. serology. ND. or by direct contact with birds. and inadequate environmental conditions are predisposing factors for clinical disease. Reduced hatchability and chick viability. aerosols. Catarrhal inflammation of nasal passages. isolation and identification of organism. Culture requires inoculation in mycoplasma-free embryos or. Survival seems to be improved on hair and feathers. coli infection).
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. exudates. The infectious agent survives for only a matter of days outwith birds although prolonged survival has been reported in egg yolk and allantoic fluid. Intercurrent infection with respiratory viruses (IB. Spread is slow between houses and pens suggesting that aerosols are not normally a major route of transmission. In adult birds. In others it is actually increasing because of more birds in extensive production systems that expose them more to wild birds. Occasionally arthritis. tenosynovitis and salpingitis in chickens. and in lyophilised material. Occasional encephalopathy and abnormal feathers.
Signs
         Coughing. Recovered birds remain infected for life. virulent E. and to a lesser extent fomites. Nasal and ocular discharge. trachea and bronchi. demonstration of specific DNA (commercial PCR kit available). though infection rates are high.
Post-mortem lesions
     Airsacculitis. ART). In turkeys it is most associated with severe sinusitis (see separate description in the turkey section). Pasteurella spp.

tylosin. Elisa is accepted as the primary screening test in some countries. synoviae and M. Differentiate from Infectious Coryza. HI may be used. all-in/all-out production.-free stock. meleagridis(turkeys). Productivity in challenged and vaccinated birds is not as good as in M. In some circumstances preventative medication of known infected flocks may be of benefit. Live attenuated or naturally mild strains are used in some countries and may be helpful in gradually displacing field strains on multi-age sites. M. viral respiratory diseases.g. Infectious Sinusitis . Transmission may be transovarian. hatchingeggs and chicks.g. Effort should be made to reduce dust and secondary infections. Morbidity is low to moderate and mortality low. Some inactivated vaccines for other diseases induce 'false positives' in serological testing for 3-8 weeks.Turkeys
Introduction
A slow onset chronic respiratory disease of turkeys often with severe sinusitis and associated with Mycoplasma gallisepticuminfection. aerosols.
Treatment
Tilmicosin. suspect reactions are examined further by heat inactivation and/or dilution. generally as a confirmatory test. vitamin A deficiency.
Mycoplasma gallisepticum infection. though in many countries this infection is now rare in commercial poultry. and fomites. or by direct contact with birds. tetracyclines. PCR is possible if it is urgent to determine the flock status. other Mycoplasma infections such as M. Aspergillosis. biosecurity. therefore M. It is seen worldwide.. and routine serological monitoring. fluoroquinolones.g. These programmes are based on purchase of uninfected chicks.
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. spiramycin. infection status is important for trade in birds. subsequent stress may cause recurrence of disease. The route of infection is via the conjunctiva or upper respiratory tract with an incubation period of 6-10 days. exudates. Recovered birds remain infected for life.
Prevention
Eradication of this infection has been the central objective of official poultry health programmes in most countries. Suspect flocks should be re-sampled after 2-3 weeks.Serology: serum agglutination is the standard screening test.

Survival seems to be improved on hair and feathers.The infectious agent survives for only a matter of days outwith birds.
Signs
       Coughing. PCR is possible if it is urgent to determine the flock status. fluoroquinolones. These are based on purchase of uninfected poults. Culture. Swollen sinuses.
Diagnosis
Lesions. Suspect colonies may be identified by immunofluorescence. although prolonged survival has been reported in egg yolk and allantoic fluid. HI may also be used. tylosin. spiramycin. tetracyclines.
Post-mortem lesions
    Swollen infraorbital sinuses. Stunting. Suspect flocks should be re-sampled after 2-3 weeks. especially Turkey Rhinotracheitis. Pericarditis. all-in/allout production. Slow growth. isolation and identification of organism. intercurrent viral disease such as Newcastle disease (even lentogenic) and Turkey Rhinotracheitis are predisposing factors. Airsacculitis. more commonly in Mycoplasma Broth followed by plating out on Mycoplasma Agar. Some inactivated vaccines induce 'false positives' in serological testing. Stress. of swabs taken from the trachea or lesions. serology. Nasal and ocular discharge.
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. demonstration of specific DNA (commercial kit available). requires inoculation in mycoplasma-free embryos or. Inappetance. In some circumstances preventative medication of known infected flocks may be of benefit. Leg problems. and in lyophilised material. Perihepatitis. suspect reactions are examined further by heat inactivation and/or dilution. Serology: serum agglutination is the standard screening test. and biosecurity. Effort should be made to reduce dust and secondary infections.
Treatment
Tilmicosin. Differentiate from viral respiratory disease. often with inspissated pus.
Prevention
Eradication of this infection has been the central objective of official poultry health programmes in most countries. malnutrition.

and can occur in other poultry and wild bird species.
Diagnosis
Shows cross reaction in IFA to M.
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.g. Infection occurs via the conjunctiva or upper respiratory tract and transmission among poults may be vertical.
Prevention
As for M.
Signs
 Swollen sinuses.g.
Treatment
As for M. Reduced hatchability. perhaps because all affected embryos fail to hatch. venereal or horizontal. Leg lesions can be shown in inoculated birds but do not seem to occur naturally.
Introduction
Infection with Mycoplasma iowae is seen in turkeys.
Signs
  Embryonic mortality.
Post-mortem lesions
 Stunted embryos with hepatitis and enlarged spleens. although DNA homology is only 40%. ducks (France).
Mycoplasma iowae infection.g. some with down abnormality.Mycoplasma immitans infection
Introduction
Infection with Mycoplasma immitans is seen in geese.
Post-mortem lesions
 Sinusitis. M.i. and partridges (UK).

Slow growth. Pathogenicity is quite variable.
Treatment
Pressure differential dipping has been used where breeder flocks are infected. This can increase hatchability by 510% in this situation. purchase of M.
Signs
       Reduced hatchability.-free stock. maintenance of this status by good biosecurity.
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. with transovarian and then lateral spread in meat animals.
Mycoplasma meleagridis infection.
Introduction
A disease of turkeys characterised by respiratory and skeletal problems caused by Mycoplasma meleagridis. Infected parents may be asymptomatic. though up to 25% of infected birds show lesions at slaughter. Predisposing factors include stress and viral respiratory infections. Leg problems. Infection is via the conjunctiva or upper respiratory tract with an incubation period of 6-10 days. Stunting. The organism has also been isolated from raptors. For eradication purposes egg injection provides more consistent dosing per egg than does egg dipping. it occurs in most turkey-producing countries but is now much rarer in commercial stock. Mild respiratory problems.Diagnosis
Isolation and identification of the causative organism from dead-in-shell embryos. The infective agent does not survive well outside the bird. Antibiotics that have been used are tylosin and enrofloxacin. Mortality is low. Transmission is venereal in breeders. When the vacuum is released the eggs draw in antibiotic solution which is subsequently absorbed through the shell membranes.m. Crooked necks.
Prevention
Eradication of the infection from breeding stock. In adult birds though infection rates are high.i. Specialised dip tanks are subjected to negative pressure which partially collapses the air cell of the submerged eggs. M. morbidity may be minimal. Infected eggs result in widespread distribution of infection and increased risk of further vertical transmission.

In some circumstances preventative medication of known infected flocks may be of benefit. demonstration of specific DNA (commercial kit available). Infection rates may be very high. It occurs in most poultry-producing countries. Airsacculitis (rarely) seen in adult birds.
Prevention
Eradication of this infection is also possible using similar techniques as for Mycoplasma gallisepticum.
Treatment
Tylosin. Serology: SAG used routinely . Spread is generally rapid within and between houses on a farm. 11-21 days following contact exposure. Survival of the infectious agent outwith the bird is poor but fomite transmission between farms is important. or lateral via respiratory aerosols and direct contact. Transmission may be transovarian.
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. isolation and identification of organism.s. Effort should be made to reduce dust and secondary infections. Culture requires inoculation in mycoplasma-free embryos or. Infection is via the conjunctiva or upper respiratory tract with a long incubation period. Infected males are particularly prone to transmit infection and may warrant special attention. Predisposing factors include stress and viral respiratory infections.Post-mortem lesions
  Airsacculitis in infected pipped embryos and poults. Infectious Synovitis
Introduction
Infection with Mycoplasma synoviae may be seen in chickens and turkeys in association with synovitis and/or airsacculitis. serology. especially in commercial layer flocks. Birds infected from their parents seem to be immuno-tolerant and particularly prone themselves to transmit.
Mycoplasma synoviae infection. tetracyclines. more commonly in Mycoplasma Broth followed by plating out on Mycoplasma Agar. M. Differentiate from Mycoplasma gallisepticum. spiramycin. other respiratory viruses. whilst illness is variable and mortality less than 10%. These are based on purchase of uninfected poults.culture used to confirm. Suspect colonies may be identified by immuno-fluorescence. Infected birds do develop some immunity. Mycoplasma synoviae. and biosecurity.
Diagnosis
Lesions. fluoroquinolones. all-in/all-out production. Vaccines are not normally used.

Signs
        There may be no signs. Depression. Inappetance. Ruffled feathers. Lameness. Swelling of hocks, shanks and feet (sometimes severe and bilaterally asymmetrical). Faeces may be green in acute infections. Effects on egg production appear to be minor under good management.

Post-mortem lesions
       Joints and tendon sheaths have viscid grey to yellow exudate. Some strains can lead to amyloidosis. Swollen liver, spleen and kidney have been seen in the past but are not common now. Green liver. Exudate becomes caseous later. Sternal bursitis. Airsacculitis - usually in heavy broilers and associated with condemnations.

Prevention
Eradication of this infection is also possible using similar techniques as described forMycoplasma gallisepticum. These are based on purchase of uninfected chicks, all-in/allout production, and biosecurity. Maintenance of Mycoplasma synoviae free status seems to be more difficult than for Mycoplasma gallisepticum. In some circumstances preventative medication of known infected flocks may be of benefit. Vaccines are not widely used though they are available in some countries. Infected birds do develop some immunity to the effects of repeated inoculation.

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M.Abubakar.Tahir

Mycotoxicosis
Introduction
Mycotoxicosis refers to all of those diseases caused by the effects of toxins produced by moulds. Disease is often subclinical and may be difficult to diagnose. Problems occur worldwide, but especially climates with high temperature and humidity and where grain is harvested with high water content. Economic impact is considerable in some countries. A number of different types are recognised: aflatoxins are produced by Aspergillus flavus; T2 fusariotoxins by Fusariumspp. (mouth lesions and thin eggshells); ochratoxins byAspergillus ochraceus (interferes with functions of kidney, proventriculus and gizzard); rubratoxin by Penicillium rubrum(interferes with thiamine metabolism and causes symptoms of deficiency). Other mycotoxins certainly occur. Mortality is variable but all are detrimental to bird health and are resistant to heat inactivation. The following species may be affected, in decreasing order of susceptibility: ducks, turkeys, geese, pheasants, chickens. The route of infection is by ingestion of fungal spores, which are readily carried in the air. High grain humidity, and damage due to insects, as well as poor storage conditions are major predisposing causes. Once toxins have been formed it is difficult to avoid their biological effects; they also increase susceptibility to bacterial diseases. Both fungal spores and formed toxins are generally highly resistant. Affected flocks return to normal mortality by 7 to 15 days after removal of the toxins. Some believe that mycotoxicosis is an important factor in fatty liver syndrome. Aflatoxins are known to inibit the synthesis and transport of lipids in the liver. Deficiencies of fat-soluble vitamins (A, D, E, and K) are also sometimes seen in aflatoxicosis. Multiplication of moulds in cereals requires selenium and this element is also important for the production of hepatic lipases. Aflatoxins have been shown to be carcinogenic in rodents so there may be public health issues relating to the effective control of these problems.

Post-mortem lesions
  Lesions also vary in accorance with the same factors as signs. Mycotoxins can cause damage to mucosae with which they come in contact.

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      

They can also be absorbed and affect blood coagulation, resulting in petechiae and larger haemorrhages in various tissues. Liver and kidney lesions - livers may be enlarged and fatty or show bile retention or tumours. Enteritis of variable degree may be seen. Hydropericardium. Pale bone marrow. Regression of the bursa of Fabricius. Gizzard erosions.

Diagnosis
In severe cases a presumptive diagnosis may be based on the history, signs and lesions. Histology may be beneficial in some cases, as may identification and quantification of toxins in samples of feed or feed residue. Differentiate from poor nutrition, poor management, physical damage to tissues, and infectious bursal disease.

Treatment
The most effective treatment is removal of the source of toxins. Addition of antifungal feed preservatives is also helpful. Increasing protein level in the feed until mortality reduces may also be beneficial. Administration of soluble vitamins and selenium (0.2 ppm), along with finely divided copper sulphate in the feed 1kg/ton for 7 days (where approved) has been used.

Prevention
Mycotoxicoses may be prevented by careful choice of feed raw materials, reduction in water content of the raw materials and hygienic storage. Antimycotic feed additives may also be used but may not deal with toxins already formed. Feeds with high levels of fishmeals are particularly susceptible and should not be stored for more than 3 weeks. Pelletising feed may reduce fungal counts but does not affect toxins. Certain minerals additives have been shown to bind mycotoxins and reduce their effects. Good stock control, management of feeders and bins, and avoidance of feed spillage are all important.

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phenoxymethyl penicillin.
Signs
       Depression. other debilitating diseases. in ducks possibly heavy strains.small intestine. Water medication for 3-5 days and in-feed medication for 5-7 days depending on the severity. high viscosity diets (often associated with high rye and wheat inclusions in the diet).g. contaminated feed and/or water. Mortality may be 5-50%. in drinking water.
Post-mortem lesions
     Small intestine (usually middle to distal) thickened and distended.Tahir
Necrotic Enteritis
Introduction
An acute or chronic enterotoxemia seen in chickens. amoxycillin). high levels of most growth promotors and normal levels of ionophore anticoccidials also help. Infection occurs by faecal-oral transmission.
Prevention
Penicillin in feed is preventive. neomycin and erythromycin are used in the USA. Probiotics may limit multiplication of bacteria and toxin
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. Closed eyes. or Bacitracin in feed (e. Sudden death in good condition (ducks). turkeys and ducks worldwide.
Diagnosis
A presumptive diagnosis may be made based on flock history and gross lesions Confirmation is on the observation of abundant rods in smears from affected tissues and a good response to specific medication. usually in less than 48 hours. usually around 10%.M.Abubakar. diet (high protein).g. Reflux of bile-stained liquid in the crop if upper small intestine affected. Inappetance. Affected birds tend to be dehydrated and to undergo rapid putrefaction. Spores of the causative organism are highly resistant. Predisposing factors include coccidiosis/coccidiasis. Immobility. Ruffled feathers. Intestinal mucosa with diptheritic membrane. Dark coloured diarrhoea. 100 ppm). usually of the mid. caused by Clostridium perfringens and characterised by a fibrino-necrotic enteritis. Treatment of ducks is not very successful. Intestinal contents may be dark brown with necrotic material.
Treatment
Penicillins (e.

Affected species include chickens. Higher mortality is seen in velogenic disease in unvaccinated stock. conjunctivitis in man).Neurotropic Velogenic . fomites. It is not usually vertical (but chicks may become infected in hatcheries from contaminated shells). The virus involved is Paramyxovirus PMV-1. sometimes subclinical. The sample at the bottom of the picture is still focal. the upper has formed a thick crust of necrotic material. In many countries local regulations or market conditions prevent the routine use of many of these options.
Newcastle Disease (Paramyxovirus 1)
Introduction
Paramyxovirus 1 or Newcastle Disease is a highly contagious viral disease affecting poultry of all ages. turkeys. which is of variable pathogenicity. Intestinal lesions are absent. The condition is rarely diagnosed in ducks but is a possible cause of production drops/fertility problems. birds.Acute and fatal in chickens of any age causing neurological and some respiratory signs.production. Other species can be infected including mammals occasionally (e.
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. pigeons and ducks. Four manifestations have been identified:     ND . ND . Strains can be developed as vaccines.Mild disease. visitors and imported psittacines (often asymptomatic).Lentogenic . less for turkeys and relatively apathogenic in psittacines. Severe lesions of necrotic enteritis affecting the small intestine of broilers. ND .Velogenic Viscerotropic (VVND) . ND . These viruses have sometimes been used as vaccines in previously immunised birds.
Transmission is via aerosols. Morbidity is usually high and mortality varies 0-100%.sometimes called 'asiatic' or exotic.Mortality and nervous signs in adult. Can affect any age.g. It is highly virulent for chickens.Mesogenic .
Figure 25. respiratory or reproductive systems. Signs are typically of disease of the nervous.

In some countries it has been customary to provide antibiotics prophylactically during periods of anticipated vaccinal reaction. A typical programme may involve Hitchner B1 vaccine at day old followed by LaSota-type vaccine at 14 days. Severe haemorrhagic and necrotic lesions in proventriculus and Peyers patches in the intestines of a broiler chicken suffering from one of the severe forms of Newcastle disease (viscerotropic velogenic). Elisa is now also used. snicking.Prevention
Quarantine. Vaccination programmes should use vaccines of high potency.
Non-starter and 'Starve-out's
Introduction
This is a condition seen worldwide in young chickens and turkeys due to failure to begin normal food consumption. These tests do not directly evaluate mucosal immunity. Mortality peaks at 3-5 days for birds that fail to eat at all. whereas it tends to peak between 6-10 days for chicks that begin eating but then cease. To prevent or reduce vaccinal reactions in young chicks it is important that day old have uniform titres of maternal immunity. The LaSota-type vaccine may even repeated at 35-40 days of age if risk is high. Acute viral infections or heavily contaminated drinking water may have a similar effect to bad management in reducing feed intake. and occasionally gasping due to a plug of pus in the lower trachea. and is associated with difficulty maintaining brooding temperature and poor management of feeders and drinkers. Morbidity is up to 10% and mortality close to 100%. Use of Mycoplasma gallisepticum free stock under good management reduces the risk of vaccinal reactions. HI has been used extensively. however. It is commonest in progeny of young parent flocks (relatively small yolks) or where managers are inexperienced. It is common to monitor response to vaccination. which are adequately stored and take into account the local conditions. vaccination. especially in breeding birds by the use of routine serological monitoring.
Inactivated vaccines have largely replaced the use of live vaccines in lay but they do not prevent local infections. all-in/all-out production.
Figure 28.
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. Use of spray application is recommended but it needs to be applied with care to achieve good protection with minimal reaction. biosecurity. Vaccinal reactions may present as conjunctivitis.

Deep Pectoral Myopathy
Introduction
This condition is so named because it was first identified in adult breeding turkeys in Oregon State. age of collection and weight of hatching eggs. Without adequate blood supply the tissue of the muscle begins to die. or suffer necrosis. good drinking water hygiene.
Post-mortem lesions
     Crop empty. It is caused by a reduction in the blood supply to the deep pectoral muscles. Genetics may play a role in that it has been suggested that blood supply to the affected muscles is reduced in some heavy meat type birds.Signs
 Failure to grow. Differentiate from omphalitis/ yolk sac infection. aspergillosis. nutrition of young parents. It has since been seen in turkeys.
Diagnosis
Based on post-mortem lesions. Gizzard may be impacted with litter.
Treatment
Correction of management problems. any swelling of the muscle tends to cut off the blood supply. Gall bladder distended.
Oregon Disease . in broiler parent chickens and also in large broiler chickens in various places.
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. bile staining of adjacent tissues. good hygiene and biosecurity in brooding areas to minimise early disease challenges. It does not usually cause any mortality or obvious clinical signs and so it is usually identified after slaughter. Poor development.
Prevention
Review brooding management. Because it is enclosed in a relatively unyielding membrane. The condition can be reproduced by causing intense exercise of this muscle. Most organs normal. soluble multivitamin supplementation may help.

in particular excessive exercise. artificial insemination in breeding turkeys.
Treatment
Not applicable. and.
Diagnosis
Lesions. If inactivated vaccines are administered into the breast muscle it is preferable that they go into the superficial muscle which is better able to cope with swelling.
Post-mortem lesions
  Acute or chronic necrosis of the deep pectoral muscle on one or both sides. It may also start to be enclosed in a fibrous capsule. A typical case of the chronic stages deep pectoral myopathy in a broiler chicken. greenish yellow. If recent. If of very long duration.g. Transillumination of the breast may help identify affected carcases and may be worthwhile if the incidence is high.
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.
Prevention
Avoidance of physical damage of this muscle. If the condition is of over 7 days duration the muscle is dry and often shows greenish tinges. the muscle may be swollen and pale.Signs
 None. This will normally be due to excessive flapping in association with management activities (e. and flaking. it may become a healed scar. with oedema within it and on its surface.
Figure 26. It is very difficult to detect affected carcases in standard meat inspection. The tissue in the centre is dry. weighing birds etc). thinning operations in meat birds.

It had been previously isolated in a number of other countries. Confirmation is by isolation of the organism. Within the poultry house it is likely to be by aerosols. The infection is common in chickens and turkeys. E. ORT
Introduction
Ornithobacterium Infection is an infection of chickens and turkeys with the bacterium Ornithobacterium rhinotracheale(ORT). The range occurring in turkeys is wider than that seen in chickens. Reduced weight gain. Some uncertainty exists about mechanisms of transmission. Cultures from the trachea of birds showing typical signs are preferred. The organism grows slowly producing tiny colonies on blood agar. sneezing.
Signs
   Coughing.Ornithobacterium Infection. This can cause significant losses through condemnations. Bordetella aviuminfection. field challenge with respiratory viruses. preferably as a flock test comparing results before and after the challenge. Reduced egg production. severe bronchopneumonia. direct contact and drinkers. A range of sero-types have been identified. coli overgrowth may occur. It is a Gram-negative pleomorphic organism. tracheitis. In broiler chickens its main importance seems to be as a cause of airsacculitis in apparently healthy flocks that is only identified at slaughter. There is some evidence that hatcheries may play a role in the epidemiology.
Post-mortem lesions
 Airsacculitis. Inoculation of fresh material from a case can reproduce lung lesions similar to those caused by Pasteurella multocida infection in previously uninfected turkeys over 10 weeks of age. Most isolates are oxidase positive and galactosidase positive Serology using Elisa tests has been used. Important cofactors may include respiratory viral vaccines (Newcastle disease. It commonly exacerbates respiratory disease caused by pneumovirus infections in turkeys. age at infection etc. ventilation problems. coli infections. The slow-growing bacterium was named in 1994. Infectious Bronchitis). perhaps through survival of the organism on shell surfaces or shell membranes.
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. The severity of its effects depends on the pathogenicity of the particular strain and other risk factors such as viral infections.
Diagnosis
Clinical signs and lesions. Growth is more rapid and consistent in an anaerobic jar. and E. This was first identified as a new disease syndrome of turkeys in Germany in the early 1990s.

The lung is solid and covered by pus/ purulent exudate. Satisfactory disease control depends on good management and biosecurity. Hygiene . An inactivated vaccine is licensed for broiler parents in Europe. Vaccination of breeder flocks to protect progeny has shown benefits in chickens but. also most are sensitive to tiamulin. Initially in Germany most strains were sensitive to amoxycillin.there are issues relating to availability. Some vaccines seem to have difficulty in producing a longlasting serological response to ORT. ORT is a major problem on multi-age sites. Routine treatment . Severely consolidated lung from an acute ORT infection in 14-week-old turkey growers. Similar lesions may be found in Pasteurellosis.
Figure 27. therapy and vaccination. because of the age of slaughter. neomycin and enrofloxacin. Some work has been done on live vaccine in the USA. Tilmicosin is also effective at 10-20mg/kg and should be used in the early stages of the disease. Amoxycillin sensitivity remains good. this is unlikely to work in turkeys. cost etc.
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.Treatment
The sensitivity of ORT to antibiotic is highly variable. Preventative medication with the products listed in the previous section may be beneficial in some circumstances. it requires two doses. In the USA in 1998 all strains were sensitive to penicillins and many other microbials. chlortetracycline but not to enrofloxacin. In France and Belgium most strains were sensitive to enrofloxacin.
Prevention
This is based on good hygiene. regulation.it is very sensitive in vitro to a range of chemicals. Vaccination . though 54% were sensitive to tetracycline.amoxycillin at 250 ppm in water for 3-7 days or chlortetracycline at 500 ppm for 4-5 days.

Treatment
Not applicable .
Signs
       Lameness. turkeys and ducks seen worldwide and due to Vitamin D or calcium deficiency. Birds go off legs. Drop in production. high production.
Osteoporosis. Soft bones and beak. Cage Fatigue
Introduction
A condition of chickens. Soft-shelled eggs.
Signs
 None.
Prevention
Unknown.only identified at slaughter.Osteomyelitis Complex. Enlarged hocks. Birds rest squatting. Gram-variable pleomorphic bacteria have been isolated from affected livers and bones. The green discolouration is used to identify carcases that require closer inspection of the other tissues. Turkey
Introduction
An association has been shown between green discolouration of the livers of turkey growers at slaughter and the occurrence of inflammatory lesions of bones and/or joints.
Post-mortem lesions
 Green discolouration of the liver at slaughter.
Diagnosis
Lesions.
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. Predisposing factors include small body size.

Coughing. antioxidants.
Post-mortem lesions
 Not characteristic. Drop in egg production. Vertical transmission does not usually occur. Parathyroids enlarged. bone ash.Yucaipa Disease
Introduction
An infection of chickens. Epiphyses of long bones enlarged. Beading and fracture of ribs.
Prevention
Supplementation of vitamin D. place on litter. Wild birds are believed to be especially important. turkeys and passerine cage birds with Paramyxovirus PMV-2 results in disease with variable mortality.
Signs
    Depression.
Treatment
Over-correct ration vitamin D. Beak soft. Differentiate from Marek's disease.Tahir
Post-mortem lesions
     Bones soft and rubbery. As birds progressively mobilise skeletal calcium for egg production through lay. whereas turkeys are more severely affected. Transmission is by wild birds and fomites. signs.
Paramyxovirus 2 .M.
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. lesions. spondylitis. proper Ca and P levels and ratio. Inappetance. skeletal size and mineral content at point of lay are critical.Abubakar. depending on the species affected and whether infection is complicated by other factors and diseases.
Diagnosis
History. calcium carbonate capsules. In chickens it is usually mild.

Diagnosis
Isolation in CE. including wild bird contact and fomites. biosecurity. all-in/all-out production. HI with ND serum or DID (less cross reactions). Vaccination has been used in turkeys but may not be cost-effective. biosecurity.
Paramyxovirus-6
Introduction
Paramyxovirus PMV-6 infection of turkeys. all-in/all-out production. IFA. HA+.
Signs
  Reduction in egg production. In both cases mortality can be high and can be associated with a marked depression in growth. It is an infectious and transmissible cause of sudden increases in mortality in turkeys between 7 and 28 days of age.
PEMS and Spiking Mortality of Turkeys
Introduction
Poult Enteritis and Mortality Syndrome (PEMS) was first identified in high density turkey producing areas of the South Eastern USA in 1991. A range of
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. Mild respiratory signs. A less acute form of the disease appears to produce more of a lingering mortality.
Treatment
No specific treatment. The infection is inapparent in ducks and geese. Mortality is 0-5%. Vertical transmission does not usually occur.Prevention
Quarantine. The infection is transmitted by birds.
Prevention
Quarantine.
Post-mortem lesions
 No specific lesions. antibiotics to control secondary bacteria.

viruses have been isolated from affected flocks. Droppings watery. Emaciation.
Post-mortem lesions
     Dehydration. Effective terminal disinfection.
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. lesions. Good quality diets of a suitable form . Fluoroquinolone antimicrobials appear to be especially effective.mash and poor quality crumbles increase risk.
Pendulous Crop
Introduction
A complex condition of turkeys and chickens associated with coarse fibrous feed. Overdistension of crop in young birds because of an interruption in feed supply may predispose.
Signs
        Initial hyperactivity and increased vocalisation. Increasing weakness.
Diagnosis
Signs. Picking at feed. All-in/all-out production. Muscle atrophy.
Treatment
A range of antibiotics and arsenicals have been used to control the bacterial component of this condition. To replicate the condition in full it appears to be necessary to include bacteria in the inoculum. pale brown.5-8% will encourage feed intake and recovery. Increased water consumption. eating litter. huddling. Reduced feed consumption and growth. Wet litter.
Prevention
Biosecurity to reduce the introduction of new infections into brooding facilities. Caseous cores in bursae (late in the process). Liquid intestinal contents. Weight loss. seeking heat. A highly digestible diet with fat at 7. multivitamins and milk replacer products are helpful for nutritional support in the acute phase. This syndrome is clearly distinguished from typical viral enteritis in young turkeys because of the high mortality and severe growth depression.

including crustaceans. They are found in the mucosa of crop and proventriculus causing mainly inapparent infections. Diarrhoea.
Diagnosis
Signs. Tetrameres and Cyrnea are nematodes. Lack of muscle tone.
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. ulceration. identification of worms. if these can be identified.
Treatment
None. Crop contents semi-liquid and foul smelling. Infection is by the oral route on exposure to the intermediate hosts. Emaciation in heavily infected young chicks (Tetrameres). and thickening of mucosa of proventriculus. have ulcerations and sometimes mycosis.
Signs
   Anaemia. necrosis.
Post-mortem lesions
 Inflammation. spiruroid worm parasites of poultry and game birds.
Post-mortem lesions
   Crop distended with feed.
Proventricular Worms
Introduction
Dispharynx. grasshoppers and cockroaches.Signs
 Enlargement of crop. haemorrhage. may be impacted.
Prevention
Remove predisposing factors.
Diagnosis
Macroscopic examination of lesions. lesions.

Prevention
Thorough cleaning.7 mm.
Diagnosis
Number and type of mites identified. fumigation and insecticide treatment at turnaround. organophosphates.
Signs
       Presence of grey to red mites up to 0. citrus extracts. Effective monitoring of mite numbers and implementation of control measures before birds are heavily infested improves control. Loss of condition. May cause anaemia and death in young birds.Red Mite and Northern Fowl Mite
Introduction
Arachnid mites.
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. Drop in egg production. For northern fowl mite it is essential to apply approved insecticides to the affected birds. mainly at night and may transmit fowl cholera and other diseases. Ornithonyssus bursae.
Treatment
Pyrethroids. vegetable oil and mineralbased products (both liquid sand dusts) have been used to control red mites in the environment. Pale comb and wattles. Dermanyssus gallinae. and good design of new equipment to limit harbourages for red mites. Staff complaints . feeds by sucking blood. the Common Red Mite. Spots on eggs. which are external parasites of chickens and turkeys. in nest boxes. the Northern Fowl Mite spends its entire life cycle on the bird and can multiply more rapidly as a result. carbamates. However keep in mind that the majority of the population of Dermanyssus is in the environment so it is necessary to monitor infection levels on feeder tracks. Filling of cracks and crevices.
Post-mortem lesions
 Anaemia. crevices etc.itching. cracks. Birds restless.

It may occur as an exacerbating factor in other types of respiratory disease. The virus grows well in tissue culture (CE kidney. vaccinal and field strains) and bacteria (Ornithobacterium rhinotracheale. Opinions vary as to whether adenovirus can be characterised as a primary respiratory pathogen. Avian pneumovirus. A number of respiratory viruses (Infectious Bronchitis. Transmission may be vertical and lateral. Infected birds may remain carriers for a few weeks.
Post-mortem lesions
 Mild catarrhal tracheitis. chloroform. formaldehyde and iodides work better. 'Mild Respiratory Disease'
Introduction
An adenovirus infection of chickens with a morbidity of 1-10% and a mortality of 1-10%. and by fomites.Tahir
Respiratory Adenovirus Infection.M. CE liver). lesions.
Diagnosis
History. and other factors associated with poor ventilation.Abubakar. E.
Signs
 Mild snick and cough without mortality. prevention of immunosuppression. Lentogenic Newcastle disease virus. intranuclear inclusions in liver. ammonia and other gases.
Respiratory Disease Complex
Introduction
Respiratory infections in chicken and turkeys are seen worldwide but especially in temperate poultry-producing areas in winter months. pH). Dust. temperature. at least 12 sero-types have been described and these may be isolated from healthy chickens.
Prevention
Quarantine and good sanitary precautions. coli) may be involved. may act as
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.
Treatment
None. The virus is generally resistant to disinfectants (ether.

carefully applied appropriate viral vaccines. be challenged by some of these pathogens).
Diagnosis
Lesions. The air sacs are thickened and congested.
Treatment
Antimicrobial treatment of specific bacterial infections. There is also percarditis evident (at top right).
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.catarrhal to purulent. Given that many flocks are vaccinated it is necessary to establish normal serological response in vaccinated flocks in the absence of disease (some of which may. Differentiate from Chronic Respiratory Disease (Mycoplasmosis).10%. If condemned birds are included mortality may be more than 10%. and have been cut into to reveal a cheesy (caseous) mass of pus. Conjunctivitis. Pericarditis. response to environmental changes.predisposing factors. Sneezing. serology. Rattling noises.
Signs
      Snick.
Prevention
Effective ventilation.
Post-mortem lesions
   Severe tracheitis with variable exudate . Morbidity is typically 10-20%. mortality 5. Airsacculitis. Nasal exudate. Severe airsacculitis of thoracic air sacs in a broiler close to slaughter. sanitation of drinking water.
Figure 29. Head swelling. of course.

Transmission is lateral and possibly transovarian. spleen and kidney. There is an incubation period of 5-15 days. Diarrhoea.
Treatment
None.
Post-mortem lesions
   Neoplastic lesions in liver. turkeys.
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. geese. usually higher in females than males. Severe tracheitis is broilers with respiratory disease complex. Sometimes nodules in intestine and caecae. ducks. Both tracheas were congested and the upper sample had mucopurulent material in the lumen. Lympoid Tumour Disease
Introduction
A retrovirus infection of chickens. and quail with morbidity up to 25%. Marked stunting when Marek's disease vaccine is contaminated. Leg weakness. chick inoculation. Sometimes enteritis and proventriculitis (especially in broilers infected with contaminated Marek's disease vaccine).
Diagnosis
Pathology.
Reticuloendotheliosis. and the infection can be spread by mosquitoes or in contaminated Marek's disease vaccines. A gradual increase in mortality and poor growth in broilers may be the main signs.Figure 30.
Signs
    There may be no obvious signs.

except that the adults reside in the small intestine and earthworms are not significant paratenic or transport hosts.5 g faeces).
Diagnosis
Demonstration of virus (PAGE.submit 6 x . large . turkeys. Use of a good electrolyte solution is beneficial in the acute stage of infection. columbae in pigeons. Control of secondary bacterial enteritis may require antimicrobial medication.Ascaridia
Introduction
Ascaridia sp. and A. The
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. A. Adult birds can tolerate burdens asymptomatically.Abubakar. The route of infection is oral and maximum viral excretion occurs 2-5 days post infection. are nematode worm parasites.M. galli in fowl.
Post-mortem lesions
 Viruses replicate mainly in the mature villous epithelial cells. pheasants. Virus may be found in asymptomatic birds. seen worldwide. dissimilis in turkeys. The parasite species vary: A. electron microscopy or Elisa on intestinal contents .
Treatment
No specific treatment for this infection. stout white worms up to 12 cms in length. The route of infection is oral usually by direct ingestion of the embryonated egg and there is a 5-10-week prepatent period. partridges and pigeons. guinea fowl.Tahir
Rotavirus Infection
Introduction
Rotavirus infection is seen in chickens. It is not known if vertical transmission occurs though virus has been occasionally isolated from embryonated eggs. shorter in young birds.
Prevention
Good hygiene in brooding areas. The life cycle is similar to that illustrated in the section on the caecal worm Heterakis.
Signs
 Diarrhoea.
Roundworm.

A collection of mature roundworms (Ascaridia galli) recovered from the small intestine of a layer chicken in rear. pasture rotation and regular treatment. In the bottom left quadrant there are also some immature worms. Wasting. Listlessness.
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.
Diagnosis
Macroscopic examination with identification of worms.
Prevention
Prevention of contamination of feeders and drinkers with faeces.
Figure 31. oval smooth-shelled nonembryonated eggs in faeces. Diarrhoea.
Signs
     Loss of condition. levamisole.
Treatment
Flubendazole. piperazine as locally approved.parasites may be transported by grasshoppers and earthworms and are resistant to environmental effects.
Post-mortem lesions
  Enteritis. Poor growth. especially for young birds. mainly in young birds. Worms up to 12 cm in length in duodenum and ileum.

Treatment
None. Affected birds should be culled humanely as soon as they are identified. guinea fowls. parrots. Broiler parents and brown-shell egg layers are especially susceptible. Histology may be helpful in determining if there is an underlying inflammatory process.
Post-mortem lesions
 The fresh lesion contains a haematoma with the end of the ruptured tendon within or adjacent to it. Infections still occur worldwide in non-commercial poultry but are rare in most commercial systems now. sparrows. Fowl Typhoid
Introduction
Disease caused by one of the two poultry-adapted strains ofSalmonella bacteria.
Diagnosis
Signs and lesions are obvious.Abubakar. Chickens are most commonly affected but it also infects turkeys. canaries and bullfinches.M. The bird may have the hock dropped to the floor.
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. Ruptures of ligaments and joints are also occasionally seen. If there is a greenish tinge to the area of swelling it occurred a few days previously. This can cause mortality in birds of any age. game birds. Broiler chickens have an avascular area of tendon just above the hock that is the usual site of rupture.
Salmonella Gallinarum.
Signs
  Severe lameness. Salmonella Gallinarum. Avoidance of physical stresses on the musculoskeletal system through careful handling as well as careful design and layout of equipment. Reoviral or staphylococcal arthritis or tenosynovitis may predispose but many cases have no evidence of an inflammatory response.Tahir
Ruptured Gastrocnemius Tendon
Introduction
This is a condition causing severe lameness in roaster type meat chickens and more rarely in turkeys.
Prevention
Establishment of a steady growth profile.

Treatment
Amoxycillin. clean chicks.
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. The route of infection is oral or via the navel/yolk. Thirst.Morbidity is 10-100%. Enteritis of anterior small intestine.
Post-mortem lesions
    Bronzed enlarged liver with small necrotic foci. Anaemia. Engorgement of kidneys and spleen. Tube and rapid plate agglutination tests have been the standard serological tests for many years but have only been validated for chickens. recovered birds are resistant to the effects of infection but may remain carriers. Vaccines for fowl typhoid have been used in some areas. egg eating etc. Ruffled feathers.
Diagnosis
Isolation and identification. but is susceptible to normal disinfectants. tetracylines.
Signs
      Dejection. Inappetance.
Prevention
Biosecurity. LPS-based Elisa assays have been developed but not widely applied commercially. Enrichment procedures usually rely on selenite broth followed by plating on selective media. Yellow diarrhoea. In clinical cases direct plating on Brilliant Green. Transmission may be transovarian or horizontal by faecal-oral contamination. Differentiate from Pasteurellosis. mortality is increased in stressed or immunocompromised flocks and may be up to 100%. even in adults. The bacterium is fairly resistant to normal climate. Reluctance to move. McConkey and non-selective agar is advisable. both live (usually based on the Houghton 9R strain) and bacterins. fluoroquinolones. pullorum disease and coli-septicaemia. and/or congestion. surviving months. potentiated sulponamide. As with other salmonellae.

'Bacillary White Diarrhoea'
Introduction
Disease caused by one of the two poultry-adapted strains ofSalmonella bacteria. Pullorum Disease. pale and shows focal necrosis. guinea fowls. this usually only causes mortality in birds up to 3 weeks of age.Figure 32.
Salmonella Pullorum. sparrows. Depression. mortality is increased in stressed or immunocompromised flocks and may be up to 100%. Gasping. Similar lesions can be seen in Pullorum Disease and with other causes of septicaemia in young chicks. game birds. Closed eyes. The liver on the left is normal. Morbidity is 10-80%. in young broiler chickens. The route of infection is oral or via the navel/yolk. The bacterium is fairly resistant to normal climate. It affects chickens most commonly. Transmission may be transovarian or horizontal mainly in young birds and may sometimes be associated with cannibalism. Ruffled feathers. surviving months but is susceptible to normal disinfectants. ring doves. Vent pasting. the one on the right is slightly enlarged. parrots. Salmonella Pullorum. Bacterial septicaemia caused by Salmonella Gallinarum. but also infects turkeys. White diarrhoea. ostriches and peafowl. Occasionally it can cause losses in adult birds. Loud chirping.
Signs
         Inappetance. usually brown-shell egg layers. It still occurs worldwide in noncommercial poultry but is now rare in most commercial systems.
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. Lameness.

liver. but S. Intestinal or caecal inflammation. S.
Salmonellosis. McConkey and non-selective agar is advisable. Differentiate from Typhoid. Gallinarum. S. S. Vaccines are not normally used as they interfere with serological testing and elimination of carriers.
Prevention
Eradication from breeder flocks. in the environment or in rodent populations. Newport. and also other than S. S. Bredeney are among the more common isolates. S. Even if these infections do not cause clinical disease. Typhimurium (which are considered separately). poteniated sulponamide. fluoroquinolones.
Diagnosis
Isolation and identification. other enterobacteria. paracolon. Enrichment procedures usually rely on selenite broth followed by plating on selective media. Anatum. They infect chickens. Urate crystals in ureters.Post-mortem lesions
     Grey nodules in lungs. their presence may be significant with respect to carcase contamination as a potential source of human food poisoning. Sero-types vary. chilling and omphalitis
Treatment
Amoxycillin. The route of infection is oral and transmission may be vertical as a result of shell contamination. it may become established on certain farms. turkeys and ducks worldwide. Pullorum. In clinical cases direct plating on Brilliant Green. recovered birds are resistant to the effects of infection but may remain carriers. fomites and feed (especially protein supplements but also poorly stored grain). gizzard wall and heart. Derby. Caecal cores. Enteritidis andS. As with other salmonellae. Many species are intestinal carriers and infection is spread by faeces. Montevideo. Paratyphoid. Regardless of the initial source of the infection. Paratyphoid Infections
Introduction
Salmonellae bacteria other than the species specific sero-typesS. tetracylines. Certain sero-
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.
Morbidity is 0-90% and mortality is usually low. Splenomegaly. are capable of causing enteritis and septicaemia in young birds.

Rappaport-Vassiliadis) followed by plating on two selective media will greatly increase sensitivity. Loss of appetite and thirst. other bacterial infections and ornithosis (in ducks). Chemotherapy can prolong carrier status in some circumstances. Temperatures of around 80°C are effective in eliminating low to moderate infection if applied for 1-2 minutes.types are prone to remain resident in particular installations (e. but are susceptible to disinfectants that are suitable for the particular contaminated surfaces and conditions.
Treatment
Sulphonamides. Diarrhoea. Vent pasting.g. Predisposing factors include nutritional deficiencies.
Post-mortem lesions
        In acute disease there may be few lesions. This approach is often used in the heat treatment of feed. Differentiate from Pullorum/Typhoid. tetracyclines. or absent. amoxycillin. Dehydration.
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. fluoroquinolones. In clinical cases direct plating on Brilliant Green and McConkey agar may be adequate.g. Focal necrotic intestinal lesions. Enrichment media such as buffered peptone followed by selective broth or semi-solid media (e. Dejection.
Signs
       Signs are generally mild compared to host-specific salmonellae. Ruffled feathers. Enteritis. Senftenberg in hatcheries).
Diagnosis
Isolation and identification. chilling. neomycin. Closed eyes. Pericarditis. Cheesy cores in caecae. However this has the potential to reveal the presence of salmonellae that are irrelevant to the clinical problem under investigation. Unabsorbed yolk. The bacteria are often persistent in the environment. Good management. inadequate water. S. other enterobacteria. applied at sufficient concentrations. especially in dry dusty areas. Foci in liver.

These are the predominant sero-types associated with human disease in most countries.
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. Routine monitoring of breeding flocks. Many infected birds are culled and others are rejected at slaughter. and. Infection results in a strong immune response manifest by progressive reduction in excretion of the organism and reduced disease and excretion on subsequent challenge. clean nests. chilling. especially phage type 4. Vaccines are not generally used for this group of infections. many species are intestinal carriers and infection may be carried by faeces. all-in/all-out production. fumigate eggs. Enteritidis and S. This approach is often used in the heat treatment of feed. The bacteria are often persistent in the environment. The prevalence of S. competitive exclusion. Feed and feed raw material contamination is less common than for other sero-types.Prevention
Uninfected breeders.Typhimurium are presented separately from other sero-types of Salmonella because. inadequate water and other bacterial infections. especially in dry dusty areas. Temperatures of around 80°C are effective in eliminating low to moderate infection if applied for 1-2 minutes.
Salmonellosis.Typhimurium has remained relatively stable though the spread of the highly antibiotic-resistant strain DT104 in various farmed species gives some reason for concern. Predisposing factors include nutritional deficiencies. but are susceptible to disinfectants that are suitable for the particular contaminated surfaces and conditions. Salmonella Enteritidis. Typhimurium infections
Introduction
Salmonella Enteritidis and S. applied at sufficient concentrations. S. good feed. elimination of resident infections in hatcheries. on the one hand. care in avoiding damage to natural flora. turkeys and ducks cause problems worldwide with morbidity of 0-90% and a low to moderate mortality. has become much more common in both poultry and humans since the early 80s. hatcheries and feed mills is required for effective control. Infections in chickens. mills. The route of infection is oral. Vertical transmission may be either by shell contamination or internal transovarian contamination of yolk. secondly. breeding and grow-out farms. because there are differences in the epidemiology as compared to other salmonellae. these bacteria are often specifically cited in zoonosis control legislation. fomites and on eggshells.

competitive exclusion. Routine monitoring of breeding flocks. hatcheries and feed mills is required for effective control. It is possible to detect reactions with specific antigens in agglutination tests but competitive and direct Elisa tests are more commonly used today. fluoroquinolones in accordance with the sensitivity. mills. Differentiate from Pullorum/Typhoid.E.Pullorum serum agglutination tests.
Treatment
Sulphonamides. Closed eyes. However this has the potential to reveal the presence of salmonellae that are irrelevant to the clinical problem under investigation. Unabsorbed yolk. infection
Diagnosis
Isolation and identification.Signs
       Dejection. Rappaport-Vassiliadis) followed by plating on two selective media will greatly increase sensitivity. In clinical cases direct plating on Brilliant Green and McConkey agar may be adequate.
Post-mortem lesions
          In acute disease there may be few lesions. Chemotherapy can prolong carrier status in some circumstances. coli. Vent pasting. good feed. fumigate eggs. Perihepatitis. S. Dehydration. Misshapen ovules in the ovaries in S. Enrichment media such as buffered peptone followed by selective broth or semi-solid media (e. Lost of appetite and thirst. Foci in liver. breeding and grow-out farms. neomycin. Ruffled feathers. Enteritis.g. tetracyclines.Enteritidiscauses cross-reactions which may be detected with S.
Prevention
Uninfected breeders. elimination of resident infections in hatcheries. Pericarditis. clean nests. Stunting in older birds. other enterobacteria such as E. Good management. Cheesy cores in caecae. Infection
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. amoxycillin. Diarrhoea. Focal necrotic intestinal lesions. Early depletion of infected breeding stock is required in some countries such as those of the European Union. care in avoiding damage to natural flora. all-in/all-out production.

Death. The control of infection in this area is probably achieved by ciliated epithelium that mostly wafts a carpet of mucus towards the cloaca. Vaccines are increasingly being used for S. or may proceed upwards from the cloaca.results in a strong immune response manifest by progressive reduction in excretion of the organism and reduced disease and excretion on subsequent challenge. Infection may spread downwards from an infected left abdominal air sac. coliand occasionally Salmonella spp. Some birds may 'lay' a caseous mass of pus (which may be found in a nest or on the egg belt).
Post-mortem lesions
   Slight to marked distension of oviduct with exudate. which normally has many millions of potentially pathogenic bacteria.). May form a multi-layered caseous cast in oviduct or be amorphous. Anything that damages the epithelium or disturbs normal oviduct motility is likely to increase the likelihood of salpingitis. leaking urates. both inactivated (bacterins) and attenuated live organisms. Enteritidis and S. It is a complex condition of chickens and ducks associated with various infections including Mycoplasma and bacteria (especially E. Systemic viral infections that cause ovarian regression or damage to the oviduct or cloaca. Lesions. are especially prone to increasing salpingitis.
Salpingitis
Introduction
Salpingitis is an inflammation of the oviduct. Bacteriology of oviduct.
Signs
     Sporadic loss of lay.
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. Typhimurium infection. Distended abdomen.
Diagnosis
Use the signs to select birds for culling and post-mortem investigation. Damaged vents. The oviduct is a hollow tube joining the normally sterile environment of the body cavity with the cloaca. Peritonitis.

Morbidity is 10-20%.
Post-mortem lesions
 None.
Diagnosis
Clinical examination.
Signs
  Stand on toes shaking.
Prevention
Control any septicaemia earlier in life. immunise effectively against respiratory viral pathogens common in the area. Use of a suitable antimicrobial may be beneficial for birds in the early stages and if associated with efforts to minimise risk factors. exclusion of other problems. possibly associated with tendon injury. Shaking or quivering of legs after rising. releasing poults into larger areas and in handling heavier birds.
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.
Treatment
Multivitamins.
Prevention
Care in transport of brooded poults. aspirin may be helpful if locally approved.Treatment
Birds with well-developed lesions are unlikely to respond to medication.
Shaky Leg Syndrome
Introduction
A condition of turkeys with a course of often 3-4 weeks. use healthy parent flocks.

Males are more susceptible than females. In order to reproduce the typical condition the affected birds are subject to 4 hours without feed and then a mild physical stress such as spraying with cool water. Orange mucoid droppings. Filtered intestinal contents from affected flocks appear to be capable of reproducing the condition. electrolytes and glucose solution to flock.
Post-mortem lesions
   Mild enteritis. This appears to be a multifactorial condition. rapidly growing broiler chickens. Minimise stress. Death. Mortality drops off as sharply as it started.
Signs
     Tremor. typically 7-14day-old. and/or carbohydrate absorption are disturbed resulting in a hypoglycaemia. Avoidance of physical stress. Avoidance of interruptions in feed supply.Spiking Mortality of Chickens
Introduction
This is a condition characterised by a sudden increase in mortality in young.
Treatment
Leave affected chicks undisturbed.
Diagnosis
Pattern of mortality. probably because they are growing faster. Birds in good condition die after showing neurological signs. suggesting a viral component.
Prevention
Good sanitation of the brooding house. Dehydration. Excess fluid in lower small intestine and caecae. Feed intake. Coma. Paralysis. Signs and lesions. Provide multivitamins.
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.

isolate in chicken eggs or chicks or poults.
Prevention
Control vectors. The bacterium is poorly resistant outside host but may be carried by Argas persicus for 430 days. Cyanosis.
Treatment
Various antibiotics including penicillin.g.
Diagnosis
Haematology. Argas persicus. geese. Weakness and progressive paralysis. Liver enlarged with small haemorrhages. Thirst. pheasants.Spirochaetosis
Introduction
The bacterium Borrelia anserina infects chickens. is an intestinal spirochaete that can be associated with inflammation of the large intestine in a broad range of mammals and birds. turkey. e. Often diarrhoea with excessive urates. Necrotic foci.
Signs
      Depression. diarrhoea.
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. reduced egg production. Drops in egg production may be seen in both systemic and intestinal forms
Post-mortem lesions
     Marked splenomegaly. and occasionally by infected faeces. It has been associated with typhilitis. and egg soiling in chickens. Spleen mottled with ecchymotic haemorrhages. It is transmitted by arthropods. Mucoid enteritis. ducks. vaccines in some countries. grouse and canaries with morbidity and mortality up to 100%. previously known as Serpulina pilosicoli. Brachyspira pilosicoli.

Abubakar.
Prevention
Selection for satisfactory conformation in primary breeding.
Post-mortem lesions
 Anterior-posterior rotation of the bodies of the last or penultimate thoracic vertebrae resulting in scoliosis just anterior to the kidney.
Treatment
None.
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.M. These are cross-sections of the spinal column of 4-5-weekold broilers.
Figure 33. with rotation of the body of the vertebra and the pinching of the spinal column that causes paralysis. Use of wings to help in walking. May walk backwards. Kinky-back
Introduction
A complex condition of broiler chickens with a morbidity of 1-5% and low mortality associated with rapid growth and possibly having a genetic component. legs extended forward.
Signs
   Sitting on hock or rumps.
Diagnosis
Symptoms.Tahir
Spondylolisthesis. That on the left shows the typical lesion of spondylolisthesis. lesions. The sample on the right is normal.

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. Damaged skin due to nutritional deficiencies (such as of biotin) may also be a point of entry. Wounds. The type of chick box liners and the feeding papers used in the brooding house can also influence the occurrence of the condition. Staphylococcal Arthritis. mainly S.M. Morbidity is usually low and mortality 0-15% though affected birds will often be culled on humane grounds. avoidance of excessive hatching egg storage.
Post-mortem lesions
 Gross lesions are not usually evident.
Signs
 Legs splay and chick is unable to stand.
Staphylococcosis. Bumble Foot
Introduction
Caused by Staphylococcus bacteria. either accidental or induced by interventions such as beak trimming.Abubakar. These include good breeder nutrition. Infection is usually by the respiratory route with an incubation period of 2-3 days seen after artificial infection.Tahir
Spraddle Legs or Splay Leg
Introduction
Occurs in all species in the recent hatchling. and careful monitoring of incubation conditions.
Treatment
None.
Prevention
All measures that improve chick vitality at hatching are beneficial in reducing this problem.
Diagnosis
Clinical signs. aureus and seen in chickens and turkeys worldwide. and toe trimming may be a portal of entry with subsequent spread via the bloodstream to the typical sites of lesions.

Streptococcus bovis Septicaemia
Introduction
An infection of ducks with the bacterium Streptococcus bovis. Mycoplasma spp. trauma. toe clipping).
Treatment
Antibiotics. e..
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. particularly of parent birds.Transmission occurs in the hatchery and in the general farm environment. Some sudden deaths from acute septicaemia if very heavy challenge. Good management.g. Infected joints may have clear exudate with fibrin clots.. synoviae. and imunosuppression. This condition is a cause of sudden deaths in ducklings of 2-3 weeks of age.
Diagnosis
Lesions. chronic stress. Competitive exclusion with a non-pathogenic Staphylococcushas been shown to be effective (no commercial products yet available based on this technology). Low mobility. Lameness. low stress and prevention of immunosuppression from any cause will all tend to help. This may progress to abscess formation in these areas.
Signs
     Ruffled feathers. Possibly vaccination against reovirus infection. most commonly in the plantar area of the foot or just above the hock joint. Swollen above the hock and around the hocks and feet. Recovered birds may have some immunity but vaccination with staphylococci has not been found to be helpful in preventing the disease to date. and by fomites. Salmonella spp. Differentiate from septicaemia or tenosynovitis due to Colibacillosis.
Post-mortem lesions
  Tenosynovitis. isolation and identification of pathogen. Predisposing factors include reovirus infection. especially M. in accordance with sensitivity. the hatchery and in any intervention or surgery (processing.
Prevention
Good hygiene in the nest.

Signs
 Sudden death in convulsion. The atria of the heart have blood. Liver congestion. isolation. the ventricles are empty. Affected well-grown birds may appear to have died from smothering.
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.
Prevention
Good husbandry and hygiene. Splenic hyperplasia. It can be induced by lactic acidosis and about 70% of birds affected are males.
Post-mortem lesions
     Intestine filled with feed.).
Diagnosis
History. lesions. extra care in the immediate post-brooding period.Signs
  Sudden deaths. Haemorrhages in muscles and kidneys. Serum accumulation in lung (may be little if examined shortly after death). possibly metabolic. Sodium deficiency can appear very similar at about the same age . Livers heavier than those of pen-mates (as a percentage of bodyweight. most are found lying on their back. 'Flipover'
Introduction
A condition of broiler chickens of unknown cause.
Sudden Death Syndrome.
Treatment
Amoxycillin. Lung congestion and oedema.affected birds respond well to saline injection and will actively seek out salt scattered in the litter.
Post-mortem lesions
    Beak cyanosis. Leg weakness or incoordination in a few birds.

or birds' access to them. feed restriction.
Treatment
Flubendazole is effective at a 60 ppm in diet.Diagnosis
Birds found on back with lack of other pathology. use of dawn to dusk simulation and avoidance of disturbance. Check your local regulations.
Post-mortem lesions
 Occupy space in intestine and create small lesions at point of attachment. Most have intermediate invertebrate hosts such as beetles or earthworms. low intensity light. lighting programmes. they may not be host specific. Cestodes
Introduction
Cestodes are tapeworms that are seen in many species.
Signs
 It is doubtful if any signs are produced under most circumstances.
Prevention
Lowering carbohydrate intake (change to mash).
Diagnosis
Identification of the presence of the worms at post-mortem examination.
Treatment
None possible.
Prevention
Control the intermediate hosts.
Tapeworms. however it may not have a zero withdrawal in commercial egg layers.
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.

TD
Introduction
A complex condition seen in chickens.
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. mild lesions may require histology to distinguish from other problems. small ovoid lacunae and more matrix than normal.a mass of avascular cartilage with transitional chondrocytes. in decreasing order of frequency.
Tibial Dyschondroplasia. chloride levels and acid/base balance.
Treatment
None. Differentiate from rickets. and proximal metatarsus.
Diagnosis
Gross pathology.
Prevention
Genetic selection using the Lixiscope to identify bone phenotype. It may be associated with rapid growth and have a nutritional factor. Vitamin D3 supplementation. Lameness.
Post-mortem lesions
  Plug of cartilage in proximal end of tibia. Mature tapeworms with their heads (scolices) embedded in the intestine. modifications of calcium and phosphorus ratios. turkeys and ducks.Figure 34. Lixiscope may identify in vivo as early as 2 weeks of age. Swelling and bowing in the region of the knee joints. distal tibia. Microscopically .
Signs
   There are usually no signs unless the condition is severe.

and is also found on mammals. Morbidity is close to 100% and mortality is 5-100%. spends little time on host. Transmission is lateral with birds and faeces. It is more common in warm climates.
Signs
      Anaemia. Skin blemishes. The infection is seen in turkeys and sometimes pheasants. and may also transmit spirochaetosis and Pasteurella infection. with
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. Emaciation.
Diagnosis
Identification of the presence of the parasites. Insecticide sprays in these areas are more likely to be effective than treatment of the birds.Abubakar.
Prevention
As for red mite control. than in commercial poultry in temperate climates. Weakness. Occasionally paralysis from toxins in the tick saliva.
Transmissible Enteritis. others are avian coronaviruses closely related to infectious bronchitis virus.Tahir
Ticks
Introduction
Argas persicus is an external parasite of poultry and wild birds. Bluecomb
Introduction
Some coronaviruses involved in this condition are considered to be bovine coronaviruses (or closely related thereto). These parasites are more likely to be a problem of small scale poultry production in the tropics. Reduced productivity.
Treatment
Elimination of cracks and crevices in the poultry housing.
Post-mortem lesions
 Anaemia.M.

rapid spread. The course of the disease is about 2 weeks and birds then remain carriers for months. The viruses survive in frozen faeces for months.

Prevention
All-in/all-out production, good hygiene and biosecurity, good management.

Trichomoniasis, Canker, Frounce
Introduction
Trichomonas gallinae is a protozoan parasite of pigeons and doves (canker), raptors (frounce), turkeys and chickens. It has variable pathogenicity. Morbidity is high and mortality varies but may be high. Transmission is via oral secretions in feed and water, and crop milk.

Diagnosis
Lesions, large numbers of protozoa in secretions. Differentiate from Pox and candidiasis.

Treatment
Previously approved products included dimetridazole, nithiazide, and enheptin. Organic arsenical compounds (where approved) and some herbal products may be of some benefit in managing this problem in food animals.

Turkey Coryza
Introduction
A condition of turkeys possibly associated with Bordetella avium(previously designated Alkaligenes faecalis) infections. This bacterium usually causes mild respiratory disease in only a proportion of the flocks, and low mortality. It can be synergistic with other respiratory pathogens such as Ornithobacterium,Pasteurella spp, Mycoplasma spp. and pneumoviruses.

Treatment
None.
Post-mortem lesions
    Deep ulcers throughout intestine. Predisposing factors include Coccidiosis (especially E. but mainly ileum and caecae.
Changed angulation of tibial condyles. and E. The bacterium resists boiling for 3 minutes. lesions. necatrix. It can start suddenly and cause high mortality: 100% in quail and 10% in chickens. Watery white faeces (quail). Blood in intestine.. game birds and pigeons may also be affected. Peritonitis (if ulcers penetrate). The condition occurs worldwide. intertarsal angulation up to 10% is physiological. Diarrhoea. The route of infection is oral and transmission is from faeces of sick or carrier birds or via flies. Pale yellow membranes. Adoption of optimal nutrition and growth patterns for the economic objectives of the production system. Differentiate from perosis.
Signs
        Listlessness. which may coalesce and may be round or lenticular. tenella. Partially closed eyes. highly contagious disease of chickens and quail caused by the bacterium Clostridium colinumand characterised by ulcers of the intestines and caecae.
Diagnosis
Symptoms. IBDV and overcrowding.
Prevention
Selection for good conformation in primary breeding.
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. Drooping wings. Turkeys. greater than 20% is abnormal. E. brunetti). Ruffled feathers. Anaemia. arthritis and synovitis.
Ulcerative Enteritis. Quail disease
Introduction
Ulcerative Enteritis is an acute. Retracted neck.

low level antibiotics as per treatment.
Treatment
Streptomycin (44 gm/100 litres water). trichomoniasis. Treat for coccidiosis if this is a factor. Response to treatment should occur in 48 to 96 hours. Transmission is by faecal contamination. Inappetance.
Signs
    Dejection. all-in/all-out production. penicillin (50-100 ppm in feed).
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. amoxycillin. birds remaining carriers for months. coccidiosis. Loss of condition. Morbidity is low. Tetracyclines. Diarrhoea. Confirmation is on absence of other diseases and isolation of Cl. The infective agent is rather resistant to environment and disinfectants. Avian Infectious Hepatitis
Introduction
An insidious onset disease of chickens caused by Vibrio bacteria. salmonellosis. Wall of the caecum of a chicken suffering from ulcerative enteritis
Vibrionic Hepatitis. possibly probiotics. and disease is precipitated by stress.
Diagnosis
A presumptive diagnosis may be made on history and lesions. multivitamins. Bacitracin. colinum in anaerobic conditions (the agent is often present in pure culture in liver). necrotic enteritis. Differentiate from histomonosis ('Blackhead').
Figure 35.
Necrotic foci in liver.
Prevention
Infection-free birds.

Viral Arthritis
Introduction
Viral Arthritis is the classic, but by no means the only, manifestation of reovirus infection of chickens; at least 5 sero-types of virus occur. Morbidity is high but mortality is usually low. Transmission is by faecal contamination, and good both laterally and vertically. Birds remain carriers for over 250 days. The virus is resistant to heat, ether, chloroform, pH and environmental factors. Reoviruses vary markedly in pathogenicity and the tissue damaged. Some can cause other disease syndromes such as early chick mortality and malabsorption syndrome. Some strains have shown severe systemic disease including pericarditis in chickens. Others have caused immunosuppression by damaging the cloacal bursa in ducks.

Diagnosis
Diagnosis may be based on the history, lesions, IFA and rising antibody titre. Isolation may be readily achieved in CE yolk sac and CAM and also cell cultures (CE kidney or liver cells). Serology may be by DID, FAT or Elisa. 'Silent' infections (not associated with obvious disease) are common. Differentiate from mycoplasmosis, salmonellosis, Marek's, Pasteurella, erysipelas.

Treatment
None.

Prevention
Vaccination is ideally carried out by administering a live vaccine in rear followed by an inactivated vaccine prior to coming into lay. Most vaccines are based on strain 11/33. Rear birds in all-in/all-out production systems.

Visceral Gout, Nephrosis, Baby Chick Nephropathy
Introduction
Visceral gout is the deposition of white urates, which are normally excreted as a white cap on well formed faeces, in various tissues. Urates are also often deposited in joints and in the kidney. This condition can occur as an individual problem at any age. Outbreaks are seen in young chicks in the first week of life (baby chick nephropathy) or in flocks suffering kidney damage, or reduced water intake. All poultry species are susceptible. The kidney damage can arise from infection with certain strains of Infectious Bronchtiis virus, exposure to some mycotoxins or inadequate water intake (often because the birds have not adapated to a new type of drinker). Baby Chick Nephropathy can be due to inappropriate egg storage conditions, excessive water loss during incubation or during chick holding/transport, or inadequate water intake during the first few days of life. Very low humidity in brooding will also increase the likelihood of this problem. The timing of mortality is a reasonable guide as to the source of the problem. In Pekin/mallard ducks the condition is almost always due to inadequate water intake, whereas in muscovy ducks it is seen in breeders allowed to continue laying for over 24 weeks without a rest.

153

Signs
  Depression. Low feed intake and growth.

Post-mortem lesions
  Chalky white deposits on pericardium, liver, air sacs, peritoneum. Similar deposits may be present in joints and are usually present in the kidney.

Diagnosis
Lesions.

Treatment
This is based on correcting any management errors and encouraging water intake. Avoid any intentional or unintentional restriction in water intake. Sodium bicarbonate at 1g/litre water is mildly diuretic, however it could be counter-productive if water intake is in any way restricted.

Prevention
Careful monitoring of the conditions of hatching egg storage and incubation with a view to achieving a standard egg weight loss profile. Humidification of holding rooms and chick transporters may also be beneficial. Humidifiers in chick brooding areas are being used increasingly, especially where whole house hot air brooders are in use. Ample supplies of drinkers should be available and filled with water at house temperature prior to the arrival of the chicks.

Figure 36. Severe visceral gout in a young chick. There are white chalky deposits around the heart (in the pericardium) on all major abdominal organs, including liver, gizzard and intestines, and even in the tissues of the thigh.

Signs
These may be summarised:                     Perosis Curled Toe Paralysis Paralysis/'Stargazing' Dermatitis/Scaly Skin Mouth Lesions Conjunctivitis Anaemia Fatty Liver and Kidney Syndrome Poor Feathering Loose feathers Hatchability problems Embryo with clubbed down Thiamine (B1) Riboflavin (B2) Pantothenic acid Pyridoxine (B6) Niacin Folic Acid Cyanocobalmin (B12) Biotin
Post-mortem lesions
  Usually the gross lesions are non-specific. and egg production in the layer. damage to the intestine or increased demand for some reason may have an effect. If it is suspected that the vitamin premix may not have been included in the ration (or included at too low a level) it
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Diagnosis
Signs. Vitamin deficiencies are especially prone to cause problems of hatchability.Abubakar. because a continuous supply is required.Tahir
Vitamin B Deficiencies
Introduction
The B complex vitamins are water soluble and not stored to any significant extent in the body. Most will reduce productivity. including growth in the young animal. They act in a broad range of metabolic pathways. Some deficiencies induce characteristic microscopic effects.M. response to supplementation. Simple deficiency is now rare as diets are usually well supplemented. See the separate discussion under Chondrodystrophy and Fatty Liver and Kidney Syndrome. exclusion of specific diseases. However. The embryo is particularly dependent on having adequate supplies of vitamins deposited in the egg.

Signs
       Imbalance. Falling over. Staggering.
Prevention
Adequate supplementation of the feed with all required vitamins in levels which both support normal productivity but also have enough overage to deal with the increased demands that often occur during periods of disease challenge. Steatitis.may be appropriate (faster. Uncontrolled movements.
Treatment
If a specific vitamin deficiency is suspected.
Post-mortem lesions
      Swollen cerebellum with areas of congestion. Encephalomalacia and exudative diathesis tends to be seen in young birds of 1-5 weeks of age. The problem is associated with feed rancidity typically in diets with high fat. Necrosis. drinking water supplementation with that vitamin is ideal and usually results in a rapid response in birds that are still drinking.
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. occasionally ducklings and other birds. seen worldwide.
Vitamin E Deficiency. Encephalomalacia. Ventral oedema. Good quality multivitamin solutions are beneficial in the supportive care of a range of problems characterised by reduced feed intake. Haemorrhage. White streaks in muscle. Blood-stained or greenish subcutaneous oedema. Green wings. Muscular dystrophy is seen more frequently in older and mature birds. The balance of vitamins present should be similar to the daily nutritional requirement of the stock concerned. characterised by oxidation of various tissues and caused by Vitamin E deficiency. Muscular Dystrophy
Introduction
A spectrum of diseases of chickens and turkeys. Exudative Diathesis. Paralysis. less expensive) to analyse feed for a marker substance such as manganese rather than testing for vitamin levels.

Diagnosis
Signs. for example poor hygiene of hatching eggs. Diarrhoea. histopathology. 'bangers'. Various bacteria may be involved. It is seen where there is poor breeder farm nest hygiene.
Treatment
Vitamin E and/or selenium in feed and/or water. Closed eyes. Broad-spectrum antibiotics where there are extensive skin lesions. Disease occurs after an incubation period of 1-3 days. selenium. use of floor eggs. and poor hygiene of setters. Abnormal yolk sac contents (colour. hatchers or chick boxes. Loss of appetite. good quality raw materials. Pseudomonas.
Signs
      Dejection. turkeys and ducks due to bacterial infection of the navel and yolk sac of newly hatched chicks as a result of contamination before healing of the navel. toxicities.
Yolk Sac Infection. inadequate hatchery hygiene or poor incubation conditions. consistency) that vary according to the bacteria involved. necrotic dermatitis. antioxidant. Swollen abdomen. especially E . Staphylococci.
Prevention
Proper levels of vitamin E. Vent pasting. Morbidity is 1-10% and mortality is high in affected chicks. Inadequate incubation conditions resulting in excessive water retention and slowly-healing navels and 'tags' of yolk at the navel on hatching also contribute to the problem.
Post-mortem lesions
  Enlarged yolk sac with congestion.Proteus. lesions. Differentiate from Encephalomyelitis. feed rancidity. response to medication.
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.coli. Omphallitis
Introduction
A condition seen worldwide in chickens.

Differentiate from incubation problems resulting in weak chicks.
Treatment
Antibiotics in accordance with sensitivity may be beneficial in the acute stages. exclusion of severely soiled eggs.
Prevention
Prevention is based on a good programme of hygiene and sanitation from the nest through to the chick box (e. most will die before 7 days of age. separate incubation of floor eggs etc. Multivitamins in the first few days may generally boost ability to fight off mild infections. however the prognosis for chicks showing obvious signs is poor. clean nests.Diagnosis
A presumptive diagnosis is based on the age and typical lesions. frequent collection. There should be routine sanitation monitoring of the hatchery. Confirmation is by isolation and identification of the bacteria involved in the internal lesions. sanitation of eggs.
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